Ronald "Mac" McDonald is a co-owner and sheriff of Paddy's Pub and generally the pub's most active manager. He is roommates with his best friend from high school, Dennis Reynolds, and has been best friends with Charlie Kelly since childhood. Mac is a member of The Gang which also includes Dee and Frank. Mac is the self proclaimed Sheriff of Paddy's.
Mac gets upset at injustices, but will pounce on any opportunity he sees as a fair chance to bang or make money. He was proud of his body and weight gain during Season 7, and is secretly ashamed of returning to his regular size.
Mac is portrayed by Rob McElhenney.
Mac works out at the gym all the time. ("Charlie Has Cancer")
However, he only works out his "glamour muscles" (bis and tris) and lacks core strength. ("The World Series Defense") He is also not athletic in any sense: when he wins a contest to take a shot at a Philadelphia Flyers game, it's revealed that not only can he not play hockey at all, he can't actually ice skate either. ("Mac's Big Break")
Mac usually wears sleeveless shirts or tight tees to draw attention to his glamour muscles and to exhibit his "tribal" tattoos. ("Charlie Wants An Abortion")Mac's T-shirts usually have an ironic slogan on the front.
A major plotline during Season 7 was Mac's sudden, and quite dramatic, weight gain. Mac claimed that he was "cultivating mass", but everyone else, correctly, saw him as just getting fat. However, Mac seemed to truly believe that his weight gain was muscle, not fat. He has lost the weight again, and in the Season Eight premiere, Mac says that his "sudden and unfortunate" weight loss is putting Paddy's in jeopardy, because it might hinder his ability to do his job as head of security. (The Gang assure him that they don't feel any less safe than they did when he was fat.)
It is revealed that the reason for Mac's weight loss is that Dennis has been giving him "Mexican ephedra" pills, which caused him to lose his appetite, and telling Mac that they were "size pills". ("The Gang Gets Analyzed")
Mac is obsessed with being tough and looking like a badass. Mac constantly seeks acceptance of his parents, but his over-earnest efforts make him come off as an asshole. ("Dennis Looks Like a Registered Sex Offender") He has a series of project badass videos that involve him doing various stunts to make him look tough, badass, or like a dare devil.
Mac is jealous of other people's success.
Mac is highly competitive, and is unable to control his competitiveness. ("The Gang Gets Extreme: Home Makeover Edition") For example, when he learned that Charlie and the McPoyle brothers were possibly sexually molested by their—and Mac's—elementary school gym teacher, he feels rejected and worries that he is somehow inferior for having not been molested himself. He proceeds to research why he didn't get molested, stating that, "If the McPoyles got blown, and Charlie got blown, then why didn't I get blown?" ("Charlie Got Molested")
Although he seeks his friends' acceptance, Mac takes special pleasure in undermining, physically harming, contradicting, and publicly belittling Sweet Dee at every possible opportunity. 
Like Dennis, Mac sees himself as superior to the rest of The Gang and often attempts to prove his supremacy. For instance, in an attempt to impress Charlie and Dennis, he makes a series of "Project Badass" videotapes that consist of various idiotic stunts; however, the pair believes that Mac is just trying to "bang" them. ("Mac's Banging the Waitress")
Mac sees himself as the boss in most situations and the gang constantly complains about his bossiness.
Mac is Catholic and the only member of the group to profess a religious faith. ("The Gang Exploits A Miracle") However, this has done little to affect his general lack of ethics.
Mac is easily flattered and manipulated, especially if complimented about his body or his fighting skills. He had had an ongoing sexual relationship with a pre-op trans woman named Carmen, largely because she was so adept at flattering him about his buff body. ("Charlie Has Cancer") He claimed that he was just "putting in time" as he waited for her surgery. ("Mac Is a Serial Killer")
Mac prefers not to use condoms, even when he's having sex with people he doesn't know. ("Mac Is a Serial Killer") He only reluctantly agrees to wear a condom with the Waitress in "Mac's Banging the Waitress". There is much evidence that Mac is harboring one or more STDs. The gang gets wacked
Mac seems to have a thing for older women. He had sex with Dennis and Dee's mom, Barbara Reynolds, later saying it was the best sex of his life. ("Mac Bangs Dennis' Mom") He also expressed interest in Barbara's sister, Aunt Donna. ("The Gang Gives Frank an Intervention")
Mac places sex above friendship, and has betrayed his two best friends by dating or having sex with women very important to them:
- In high school, Mac had sex with Dennis' prom date and blamed it on Tim Murphy. ("The High School Reunion, Part 2: The Gang's Revenge")
- Later, Mac started secretly dating the Waitress despite Charlie's obsession with her. ("Mac's Banging the Waitress")
Mac frequently strives to appear "hard," usually to impress his father or friends. In reality though, he is a coward.
A Catholic, Mac is the only member of The Gang to profess a religious faith. In "The Gang Exploits a Miracle", Mac fears that the Lord show his wrath if they continue to exploit the water stain in the bar. Throughout the series Mac refuses to wear a condom during sex, because as he explains Charlie he went to Catholic school. Though Mac seems to care more about issues such as abortion, community activism, and parenting than the rest of The Gang, his views on such subjects are invariably twisted, ignorant, or prejudiced, and his actions regarding them are always hypocritical and selfish. For instance, after pretending to be adamantly pro-life in order to attract a female activist, Mac later demands that she get an abortion when he thinks she has become pregnant by him. In another instance involving the transgender woman Carmen, Mac discovers that she has married and had the operation to remove her penis. He then belittles Carmen and her husband by quoting the Bible to them and calling them "gay"; however he only reacts so because he expected Carmen to call him once she had the operation so they could date again. Mac constantly drinks alcohol like the rest of The Gang and abuses other substances, such as poppers and glue.
Throughout the series there have been insinuations that Mac is a closeted gay man. This is manifested by his obsession with men's physiques and his reactionary religious views on homosexuality. In the final scene of the season 4 episode "Mac's Banging the Waitress," Charlie says to Dennis, "Do you still get the feeling he wants to bang us? That's what this is all about" after Mac tries to demonstrate how "badass" he is by falling from the roof onto a pile of mattresses after lighting fireworks taped to his jacket that fail to ignite. In episode 2 of season 8, "The Gang Recycles Their Trash," Mac makes an attempt to kiss Dennis following a rally with Charlie and themselves. In the season 9 episode "Mac Day," Charlie says, "I know we've never said this as a group, but Mac's gay," to which the rest of The Gang agrees readily.
As part of "Mac Day", Mac forces The Gang to oil male bodybuilders, which gives him an erection. He also gets an erection in the episode when he is preaching to The Gang about the wrongs of homosexuality.
Despite insinuations that he is gay, Mac has still displayed an interest in women throughout the series, making it possible that he is actually bisexual, an option never really considered by the gang, which would explain his considerable sexual confusion.
Mac is extremely clean, and very good at keeping his apartment extremely tidy. He even cleaned up Charlie's filthy apartment after he moved in with Charlie and Frank, after Dennis kicked him out. ("Mac and Dennis Break Up")
Mac is a natural story-teller. ("How Mac Got Fat")
Mac has a delusional belief in his abilities as a security professional. He thinks of himself as "The Sheriff of Paddy's" and believes he can achieve feats of strength, assess strangers for security, and that he is highly skilled at combat. Despite this, Mac has fared poorly in physical altercations and feats of strength:
- Mac was beat up when he replaced Charlie and fought in a fight club. ("Hundred Dollar Baby")
- Mac failed in his attempt to climb the outside of Charlie's apartment building. ("The World Series Defense")
- Mac was going to beat up Bruce Mathis in a fight, but ran away from him instead. ("Dennis and Dee Get a New Dad")
- Mac attempted a roundhouse kick to the front window of a car, but missed and kicked the drivers side mirror instead. ("Paddy's Pub: The Worst Bar in Philadelphia")
- Mac does an "ocular patdown" of a hitchhiker and assessed him as safe; later, the hitchhiker steals Dee's car. ("The Gang Hits the Road")
- When Mac and Charlie are stuck at the bottom of an abandoned swimming pool that they are trying to fix, Mac attempts to get out of the pool by doing a "backflip" out of it, scaling the wall, but he doesn't even come close to getting out. ("Mac and Charlie: White Trash")
- Mac's "exit strategy" to get out of a luxury box the Gang has schemed their way into at a Phillies' game is to "spring off the balcony to safety". When Dennis points out that it's a 50 foot drop, Mac says that he will be able to "tuck and roll" and thus survive the drop unscathed. ("Frank's Back in Business")
In a similar vein, Mac also maintains a threat level assessment for the bar. Ordinarily the threat level is set to Orange, but Mac has upgraded the threat level to Yellow. ("The Gang Solves the North Korea Situation")
Mac often has trouble thinking up of the right word to convey his ideas, which Dennis is often more than glad to provide. ("Mac and Dennis Break Up")
Mac is also a poor typist. ("Mac and Charlie Write a Movie")
When Mac was young, his parents would break into houses with him on Christmas to steal presents. ("A Very Sunny Christmas")
Dennis notes that Mac only survived high school by selling weed to popular kids, and even then was considered a jerk. ("Underage Drinking: A National Concern")
- Mac is a terrible dancer. ("The Gang Dances Their Asses Off")
- Mac has at least 2 gay cousins: Brett ("The Gang Gets Racist") and Country Mac .
- When Mac was young, he had an invincible dog named Poppins. ("Mac's Mom Burns Her House Down")
- Mac has only two numbers in his phone - Charlie and Dennis. ("Dennis and Dee's Mom Is Dead")
- Mac originally introduces Mac's duster to the Gang. ("The Gang Solves the North Korea Situation")
- Mac's full name was unclear for most of the first seven seasons. In the season four episode "The Gang Cracks the Liberty Bell", the Colonial-era Mac character is referred to as "McDonald." In 7th Season "The High School Reunion", his full name is revealed to be "Ronald McDonald."
- It was initially hinted that Mac's last name is simply, "Mac". On parole papers seen in "Mac and Charlie Die (Part 1)", Mac's father's name is listed as "Luther Mac" and his mother is usually referred to as Mrs. Mac.
- In the Season 10 episode "The Gang Goes On Family Fight", Mac introduces himself as "Ronald Reynolds", and says that Frank has adopted him. Whether this is indeed the case, or this is something they made up to get him on the show, is unclear at this time.
- In the episode "Who Got Dee Pregnant?", one of the McPoyle Brothers referred to Mac as "Macwell".
- Mac often says his signature line, "What's up, bitches?", throughout the series.
- In many episodes, Mac will enter the bar announcing "I've got news," or a variation on that basic idea, to set the episode's plot in motion. The others rarely share his enthusiasm, but he usually convinces one of them to follow him, though often reluctantly. This running joke was an ironical failed in the beginning of "Chardee MacDennis".
- Mac keeps a karate trophy in his childhood room - which is not weird at all: he found it in the street. ("A Very Sunny Christmas")
- Throughout the series, Mac flashes his signature "puppy-dog look" when he is ashamed or when he proposes something reprehensibly shameful.
- Mac is one of the characters on the show who use their name (or a variant of their name) as their stage name. Among the other people who do this are Artemis and Charlie.
- Mac had always considered for Paddy's to be an "Irish Catholic bar". Here is his full-of-righteous-anger question to the Gang: "Where's our goddamn Bible?!". ("Mac Fights Gay Marriage") Later, in "Sweet Dee Gets Audited", Mac was stated it literally: "...we're an Irish Catholic bar".
- Mac is not familiar with Stalin. ("Charlie Goes America All Over Everybody's Ass")
- Mac sometimes uses the alias, Vic Vinegar. ("Frank's Back in Business")
- Mac's sexuality can sometimes be questioned ("Flowers for Charlie")
- Despite being very religious, he breaks the "rules" of the Bible multiple times during the show.
- Mac's name has been used in the titles for multiple different episodes:
- Season Two: "Mac Bangs Dennis' Mom"
- Season Three: "Mac Is a Serial Killer"
- Season Four: "Mac and Dennis: Manhunters", "Mac's Banging the Waitress", "Mac and Charlie Die (Part 1)", "Mac and Charlie Die (Part 2)"
- Season Five: "Mac and Dennis Break Up", "Mac and Charlie Write a Movie"
- Season Six: "Mac Fights Gay Marriage", "Mac's Big Break". "Mac and Charlie: White Trash", "Mac's Mom Burns Her House Down"
- Season Seven: "Chardee MacDennis: The Game of Games", "How Mac Got Fat"
- Season Nine: "Mac and Dennis Buy a Timeshare", "Mac Day"
- Season Ten: "Mac Kills His Dad", "Ass Kickers United: Mac and Charlie Join a Cult"
- Rob McElhenney, the actor who portrays Mac, is married to Kaitlin Olson, the actress who portrays Dee.
Mac has banged the following people:
- Megan - a pro-life woman who tests Mac's sincerity against abortion after a protest at a Planned Parenthood building. ("Charlie Wants an Abortion")
- Barbara Reynolds - Dennis and Dee's Mom. ("Mac Bangs Dennis' Mom")
- Z-Man's sister and Sully's sister - Mac banged both of their sisters, so he couldn't invite them to his party at Dennis' new house. ("Dennis and Dee's Mom Is Dead")
- Carmen - Pre-op trans woman. ("Mac Is a Serial Killer")
- Dominique and Tabitha - model contestants in "America's Next Top Paddy's Billboard Model Contest" (they also banged each other and let Mac watch).
- Numerous unnamed leftovers from the DENNIS System using the MAC system (Move-in After Completion). ("The D.E.N.N.I.S. System")
- Margaret McPoyle - shown in a flashback of the Halloween the year before. ("Who Got Dee Pregnant?")
- Dennis's prom date. ("She was gross.") ("The High School Reunion.")
- The Waitress
|Mac in It's Always Sunny in Philadelphia|