Attended Georgetown University with comedian Nick Kroll.
Wrote the Stefon sketches on Weekend Update with Saturday Night Live (1975) cast member Bill Hader. Bill Hader and John Mulaney got the idea of Stefon from a shy café worker and a friend who opened many clubs that 'had everything'.
Grew up in Chicago.
Does not drink alcohol.
Mulaney attended St. Clement School and then St. Ignatius College Prep.
Parents are Ellen, a law professor, and Charles (Chip) W. Mulaney, Jr., an attorney.
Mulaney's maternal great-grandfather was George J. Bates, a mayor of Salem, Massachusetts, who also served as a congressman from that state.
Is a fan of the television show Law & Order: Special Victims Unit (1999).
Studied English Literature at Georgetown University.
Owns a French Bulldog named Petunia.
Has two sisters and two brothers, the younger of which is deceased.
On July 5, 2014, Mulaney married make-up artist Annamarie Tendler.
He is of Irish, and 1/8th German, descent.
Won the 2018 Emmy Award in the Outstanding Writing for a Variety Series category for John Mulaney: Kid Gorgeous at Radio City (2018).