Ronald "Mac" McDonald is a fictional character on the FX television series It's Always Sunny in Philadelphia. Mac is Charlie's childhood friend and Dennis's high school friend and later roommate. He is a co-owner of Paddy's and generally the pub's most active manager. Mac is played by Rob McElhenney. A moral and physical coward, Mac frequently strives to appear "hard", usually to impress his father or friends, but he generally flees from confrontations and fares poorly in fights.
Mac carols 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. Throughout the series, Mac flashes his signature "puppy-dog look" when he is ashamed or when he proposes something reprehensibly shameful. He is the self-declared "sheriff of Paddy's."
For the first six seasons Mac's full name was kept anonymous as a running joke, though in the season four episode "Mac & Charlie Die," Mac's father's name is listed as "Luther Mac" on his parole papers and his mother is referred to as Mrs. Mac. In the episode "Who Got Dee Pregnant?," one of the McPoyle brothers refers to Mac as "Macwell." Mac's real name, Ronald McDonald, wasn't revealed until the season seven episode "The High School Reunion". Mac hates the name as well as his old nickname, "Ronnie the Rat," which he obtained from ratting on fellow drug dealers in high school. He prefers to be simply called "Mac."
Mac comes from a broken home; his father has been incarcerated for dealing meth and his mother is extremely apathetic and unemotional. Mac and his mother also own a dog named Poppins, who despite being extremely old and prone to eating poisonous objects appears to be practically indestructible. He sees himself as a karate expert and total badass. Mac constantly seeks the acceptance of others, especially his parents, but his over-earnest efforts make him come off as an "asshole." Earlier, under the impression that his father would possibly murder him after being paroled, Mac later receives a warm letter from his father, specifically requesting that Mac stay away from him. This letter is written as Mac's father fears that Mac's destructive tendencies could harm him. Dennis notes that the only reason Mac hung out with the popular kids in high school was because he sold them all weed and even then was considered an "asshole." Though Dennis reigns supreme as selfish and arrogant, Mac has made his fair share of selfish, inconsiderate decisions and observations.
Although he seeks his friends' acceptance, Mac takes special pleasure in undermining, physically harming, contradicting, and publicly belittling Sweet Dee at every possible opportunity, more so than Charlie or even Dennis (this hatred gains amusing subtext because the actors who play Mac and Sweet Dee are married parents in real life). Mac is considered by every member of The Gang to be a "jerk", and is nearly always the first to start betraying the others, though he does usually stick with Dennis, who is his best friend and has known him longer than anybody in The Gang but Charlie. 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 set to music; however, the pair believes that Mac is just trying to "bang" them. He had a sexual relationship with a pre-op transsexual named Carmen, for whom he claimed he was just "putting in time" as he waited for her surgery. There is much evidence that Mac is harboring one or more STDs, especially since he refuses to wear condoms, most likely due to his faith (see below).
Mac sincerely believes that he is an adept martial artist with "cat-like reflexes", and he usually wears sleeveless shirts to draw attention to his physique and to exhibit his tribal tattoos. Despite his apparent fitness, Mac generally focuses his workout time on developing his glamor muscles and is largely the weakest member in The Gang, behind everyone but Dennis. Despite his enthusiasm towards karate, he is shown to have no real expert (or basic) skills when showing off his talent, and is a coward when it comes to physical confrontations.
A Catholic, Mac is the only member of The Gang to profess a religious faith. 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 transsexual 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.
At the start of season 7, Mac has gained at least 50 pounds of fat, which he sees as a step to developing muscle ("cultivating mass" in his words) in order to go from "a tiny twink to [a] muscle-bound freak." In the episode "How Mac Got Fat", he goes into greater detail about his intentions, explaining that earlier in the series, the Gang had decided to replace themselves with avatars to run Paddy's so they could slack off. Mac's avatar was a bodybuilder. When Dee points out that the avatar doesn't look like him because he has more muscle, Mac starts gaining more weight so they'll look the same size. Eventually the Gang drops the avatar plan and everything goes back to normal, but Mac still has all the weight. The rest of The Gang agrees he looks unhealthy - Dennis is personally outraged by the sight of his gut - but Mac is indifferent to their opinions despite developing diabetes as a result of his new eating habits. He has also taken to carrying around garbage bags full of chimichangas. Rob McElhenney has stated in interviews that he wanted to make Mac fat as his own way of fighting the trend of actors on TV shows getting more attractive as a show gains more success.