Lives in California with her husband, Nick Offerman.
She is in the band Nancy and Beth.
She starred in and directed an original performance art piece, The Sweetheart Break-In. The band released a CD of some of the songs in the show, called The Supreme Music Program: The Sweetheart Break-In. They have released two other CDs: Big as a Berry and Free Again.
Graduated from Casady High School, Oklahoma City, Oklahoma.
Her father, Carter Mullally Jr., who died in 1992, was a contract player with Paramount in the 1950s. Her mother, Martha, was a model.
Megan announced her engagement to actor Nick Offerman in September 2002.
Close friend is ER (1994) actress Laura Innes. The two met at Northwestern University in the late 70s and have been friends ever since.
She studied ballet from the age of six and was a soloist with Oklahoma City's Ballet Oklahoma. She also studied at George Balanchine's School of American Ballet.
Tested for the role of Elaine on Seinfeld (1989). (According to The Seinfeld Story (2004), which aired on 25 November 2004.).
Attended Northwestern University
Has won three consecutive Screen Actors Guild (SAG) awards for Outstanding Performance by an Actress in a Comedy, and has a total of four SAG awards and two Emmy awards. Nominated for 8 Emmys and 5 Golden Globes.
First cast member of Will & Grace (1998) to win an Emmy. She won in 2000 for Outstanding Performance by an Actress in a Supporting Role: Comedy. Her co-star Sean Hayes also won that year.
Originally auditioned for the role of Grace on Will & Grace (1998), but was later cast as Karen.
Was featured in "Theater Week" as one of six "New Faces of 1995," alongside Rufus Sewell, Jude Law, Jennifer Dundas, Justin Kirk, and Billy Crudup. Ironically, she stated in that issue that she was done with television, and in five years would like "to be doing plays and musicals [in New York], and also film work."
Before she was cast to appear with Debra Messing on Will & Grace (1998), Megan Mullally appeared on an episode of Messing's previous series, Ned and Stacey (1995).
She has English and Irish ancestry.
She was nominated for a 1979 Joseph Jefferson Award for Actress in a Supporting Role in a Musical for her performance in "Bagtime" at the Wisdom Bridge Theatre in Chicago, Illinois.
Withdrew from the Broadway production of "Lips Together, Teeth Apart" because of difficulties with the director, Joe Mantello.
Starred as Beverly in the acclaimed production of Adam Bart's "The Receptionist" at the Odyssey Theatre. (notably, the longest sold-out run of a show in that theater's history), for which she was awarded the 2010 Backstage West Garland Award for Best Performance by an Actress. 
She appeared in an episode of Ned and Stacey (1995), although she didn't have a single scene with future Will & Grace (1998) co-star Debra Messing.
Megan Mullally has acted with her husband, Nick Offerman, on Will & Grace (1998), Speaking of Sex (2001), Stealing Harvard (2002), Childrens Hospital (2008), Parks and Recreation (2009), Bob's Burgers (2011), Smashed (2012), Axe Cop (2012), Ernest & Celestine (2012), The Kings of Summer (2013), Hotel Transylvania 2 (2015), and You, Me and the Apocalypse (2015).
Starred as "Elizabeth" in Mel Brooks' original Broadway musical, "Young Frankenstein" in 2008. [September 2007]
Her acting mentors were Ellen Burstyn and Elaine Stritch.
Her father, Carter Mullally Jr., appeared on The Twilight Zone: Where Is Everybody? (1959), the very first episode of The Twilight Zone (1959).
Mullally filmed some scenes for the groundbreaking 1986 film Blue Velvet (1986). She played the college girlfriend of Kyle MacLachlan's character, Jeffrey. Not only were her scenes entirely cut from the final movie but her character went totally unmentioned. (There is no sign that Jeffrey had a girlfriend before coming home and becoming romantically entangled with both Laura Dern and Isabella Rossellini.) Mullally's deleted scenes did appear in a 2011 25th Anniversary Blu-Ray edition release.
Member of the band Nancy & Beth.
She won the Women in Film Lucy Award "in recognition of her innovation in creative works that have enhanced the perception of women through the medium of television" in 2005 and the women in film Gracie Award in 2018.
She was to do a voice-over role in the Disney-Pixar film Finding Nemo (2003), but was fired from the production for refusing to do her Karen Walker voice for the film.
Before Idina Menzel, she auditioned for the role of Elsa in Disney's Frozen (2013).
She is of English, Irish and Scandinavian ancestry.
Following her graduation from Casady School in Oklahoma City, Oklahoma, she attended Northwestern University in Evanston, Illinois, where she studied English Literature and Art History, and subsequently became active in Chicago theatre.