[9][10][11][12] Mulaney's maternal great-grandparents were George J. Bates, a Republican mayor of Salem, Massachusetts, who also served as a congressman from that state, and Nora Jennings, who moved to the U.S. from Ballyhaunis, County Mayo, Ireland.

[21][22] From watching the lifestyle of the character Ricky Ricardo on the program I Love Lucy, Mulaney knew he wanted to go into show business at age five.

[10] For junior high, he attended St. Clement School[25] where, in lieu of doing reports, he and his best friend, John O'Brien, would offer to perform what they had learned as a skit.

[46] The series received poor reviews,[47][48][49][50] including playwright and The New York Times TV critic Neil Genzlinger's, who wrote "It rips off Seinfeld so aggressively that in Episode 2 it even makes fun of its own plagiarism.

The Comeback Kid received critical acclaim,[52] with David Sims of The Atlantic calling it "a reminder of everything that makes Mulaney so singular: storytelling rich with well-observed details, delivered with the confidence of someone decades older than 33".

In 2016, Mulaney received a nomination for the Primetime Emmy Award for Outstanding Writing for a Variety Special for The Comeback Kid, losing to Patton Oswalt's Talking for Clapping.

Mulaney has written five of the episodes, including "The Eye Doesn't Lie" (The Thin Blue Line) which he co-wrote with Bill Hader in 2015, "The Bunker" (The War Room), "Parker Gail's Location Is Everything" (Swimming to Cambodia) and "Mr. Runner Up: My Life as an Oscar Bridesmaid, Parts 1 & 2" (The Kid Stays in the Picture), the later two written with Hader both in 2016.

The episode features a fictional ill-fated 1970 Broadway musical, Co-op, with songs detailing the joys and pains of a New York City housing cooperative.

Mulaney's fourth stand-up comedy tour, Kid Gorgeous, kicked off its first leg in May 2017, concluding in July of that year.

[72] Mulaney provides the voice of a lead character on the animated Netflix series Big Mouth (2017–present) alongside his writing partner Nick Kroll, who co-created the show.

[76] In November 2020, Late Night with Seth Meyers producer Mike Shoemaker announced that Mulaney had joined the show as a staff writer.

[77] Mulaney returned to voice Spider-Ham in the mobile game Marvel Contest of Champions, and the promotional animated short film Back on the Air.

Candice Bergen, Tina Fey, Elliott Gould, Paul Rudd, Steve Martin, and Conan O'Brien welcomed Mulaney into the club in an on-air sketch.

Celebrity cameos include André De Shields, David Byrne, Richard Kind, Natasha Lyonne, Annaleigh Ashford, and Jake Gyllenhaal as "Mr.

[88] Critic Alan Sepinwall of Rolling Stone Magazine wrote, "It is, like Galaxy Quest, The Princess Bride, or Jane the Virgin, one of those gems that manages to simultaneously parody a genre and be an excellent recreation of it.

Variety noted that "the elephant in the room is acknowledged, but never tamed with a comprehensive account of when Mulaney relapsed, or why, or how his fame and fortune affected his addiction, or what it felt like to watch everything play out in the press.

"[96] Multiple reviews, including Esquire, compared Baby J to Richard Pryor's 1982 special Live on the Sunset Strip in regard to how frank each was about the impact of their addictions.

[102] Mulaney concluded the special by reading and commenting on sections of a "wide-ranging" interview he gave with GQ while under the influence of cocaine, saying he did not remember the answers he had given.

He guest starred in the episode "Fishes" in the Hulu series The Bear as Stevie, partner to the character Michelle Berzatto.

[106] On September 9, 2024 it was announced that Mulaney would return to Broadway in the Simon Rich play All In: Comedy About Love acting opposite Fred Armisen, Richard Kind, Renée Elise Goldsberry, and Chloe Fineman.

He has mentioned listening to a lot of Jerry Seinfeld, Dave Chappelle, George Carlin, Richard Pryor, Conan O'Brien[109] and Bob Newhart.

[108][110] When asked about his top four comedy albums, Mulaney once again cited Rock's Bring the Pain, Mitch Hedberg's Strategic Grill Locations (1999), Eddie Izzard's Dress to Kill (1998), and Dave Atell's Skanks for the Memories...

[120] In his first appearance on television in 2021, Mulaney said he had checked into a rehabilitation facility in September 2020, left the recovery program, hosted Saturday Night Live in October, and relapsed after the show.

Seth Meyers, Fred Armisen, Bill Hader, Nick Kroll, Natasha Lyonne and other friends then staged an intervention for Mulaney preceding his December 2020 rehab stint.

[126] In 2016, Mulaney appeared at an event honoring the Armed forces at Joint Base Andrews, "A Celebration of Service", organized by the USO.

[127] He performed standup comedy alongside comedians Jon Stewart, Hasan Minhaj, Mike Birbiglia, Kristen Schaal, and David Letterman.

[128] While hosting Saturday Night Live on February 29, 2020, Mulaney noted that Julius Caesar was stabbed by the Senate for being a maniac, and joked, "That would be an interesting thing if we brought that back now!

[133] During the 2023 Writers Guild of America strike, Mulaney was set to host a panel with Jon Stewart, to promote his comedy special Baby J. Mulaney cancelled the event in solidarity with the writers (both he and Stewart are guild members) and amid strike rules that prohibited members from making "For Your Consideration" appearances until an agreement was reached.

[134][135] Standup specials Musical Touring Mulaney has received numerous awards nominations and wins for his work in television.

In 2009 Mulaney won a Peabody Award alongside the writers of Saturday Night Live for their satirical work on the 2008 United States presidential election.