Lynch was born and raised in Dolton, Illinois, the daughter of a homemaker-secretary mother, Eileen (née Carney), and a banker father, Frank Lynch.Her father was of Irish descent and her mother was of Irish and Swedish ancestry. She was raised in a Catholic family and attended Thornridge High School.She received her bachelor's degree in theater from Illinois State University and her MFA in theater from Cornell University.
Lynch spent fifteen years in Chicago, acting in the Steppenwolf Theatre Company, and, at the time of her audition, was one of only two women picked to join The Second City comedy troupe.She then continued to hone her comical and improvisational skills at Annoyance Theater, playing Carol Brady in the theater's The Real Live Brady Bunch. Andy Richter played Mike Brady in the New York shows. He and Lynch became very good friends.
Lynch got her start in films in 1988, playing a small role in the film Vice Versa. In 1993 she had secondary role as a doctor alongside Harrison Ford in The Fugitive . Nearly a decade of television roles followed, including L.A. Law, Judging Amy, The West Wing, 7th Heaven, Desperate Housewives, Friends, Dawson's Creek, Felicity, Arrested Development, Lovespring International, Two and a Half Men, Weeds, Boston Legal, The L Word, Criminal Minds, Help Me Help You, Gilmore Girls, The New Adventures of Old Christine, Psych, Monk and Party Down. She also starred with John Hannah and William Fichtner in 2002's MDs and has appeared in the crime drama Criminal Minds as Spencer Reid's schizophrenic mother.
During this time, she also made numerous television commercials, including one for Frosted Flakes for an adult audience, directed by Christopher Guest. A few years later, Guest would remember Lynch as he cast actors for his dog show mockumentary, Best in Show (2000). Lynch played Christy Cummings, a butch lesbian personal dog handler to trophy wife Sheri Ann Cabot (Jennifer Coolidge). Since then, she has been a staple part of Guest's casts, appearing in the director's A Mighty Wind (2003) as porn actress-turned-folk singer Laurie Bohner and in For Your Consideration (2006) as an entertainment reporter.
Around this time, Lynch also wrote and starred in the award-winning play Oh Sister, My Sister. Originally produced in 1998, the play kicked off the Lesbians in Theater program at the Los Angeles Gay and Lesbian Center in 2004.
Audiences and critics took notice of Lynch for her turn in Judd Apatow's The 40-Year-Old Virgin. She told Fresh Air's Terry Gross the role was originally intended for a man but, at the urging of Steve Carell's wife Nancy Walls, was offered to Lynch instead. Since then, she has starred in a series of films including Role Models, Talladega Nights: The Ballad of Ricky Bobby, Alvin & the Chipmunks, Walk Hard: The Dewey Cox Story, Space Chimps, The Rocker, The Hammer, Another Cinderella Story, Ice Age: Dawn of the Dinosaurs, and Spring Breakdown.
In Julie and Julia, she played the role of Dorothy McWilliams, Julia Child's sister. Entertainment Weekly dedicated an article on their website toward the possibility of her performance receiving an Academy Award nomination.
Beginning 2009, Lynch appeared on the Fox series Glee. She won glowing reviews for her role as the aggressive cheerleading coach Sue Sylvester. Mary McNamara of the LA Times wrote, "Lynch alone makes Glee worth watching." Before her work with Glee, she was a series regular on the Starz comedy Party Down. Though the series was renewed for a second season, Lynch would not be returning due to her work on Glee.
Lynch has garnered numerous accolades and awards throughout her career, particularly for her role as Sue Sylvester. In 2005, for example, Lynch was named as one of POWER UP's "10 Amazing Gay Women in Showbiz." On December 15, 2009, Lynch received a Golden Globe nomination for Best Supporting Actress in a Series, Miniseries, or Television Film for her role on Glee; she lost to Chloë Sevigny. The series itself also received nominations in three other categories. On August 29, 2010, Lynch won the Primetime Emmy Award for Outstanding Supporting Actress - Comedy Series. And in January 2011, Lynch was awarded the Golden Globe in The Best Supporting Actress in a Series, Miniseries, or Television Film Catergory.
In addition to her current work on Glee, Lynch continues to pursue other projects. Lynch hosted Saturday Night Live on October 9, 2010; the news of her hosting was accidentally broken to her by her Glee boss, Ryan Murphy, by text message. Lynch also guest starred on the Nickelodeon show iCarly as Pam Puckett, Sam Puckett's mother, in the episode "iSam's Mom".
She starred in Comcast's XFinity ads, mainly with two different laptops and two different colored Persian cats. She also stars in LG Corp.'s Text Ed campaign to educate drivers about the dangers of texting while driving.
Lynch's first experience hosting an awards show was in 2010 when she hosted the 2010 VH1 DoSomething Awards. It was announced that she will be hosting the 2011 VH1 DoSomething Awards, airing on VH1 on August 18. Lynch hosted the 63rd Primetime Emmy Awards on September 18, 2011, only the third woman in Emmy history to host the awards show solo.According to September 19's Hollywood Reporter Lynch hosting the Emmys did not help ratings, as viewing was down 8% year over year and eight million less people watched the Emmys as watched Michael Vick's return to Atlanta on Sunday Night Football on NBC (21.5 million for Eagles-Falcons, 13.5 million for the Emmys).
Happy Accidents, was released Fall 2011 by Hyperion Voice. Lynch was inspired to write the book after reflecting upon the successes of her past year and wishing she could have told her more anxious, younger self to not worry as much. The memoir also includes detail about her years as an alcoholic and her success in battling this addiction. Lynch is openly lesbian, and married Lara Embry in 2010. A self-proclaimed animal lover, Lynch has two dogs and a cat. She has recorded a PSA for PETA encouraging the adoption of shelter animals.On February 23, 2012, it was announced that she would be the commencement speaker for Smith College's class of 2012.
In March 2012, Lynch was featured with Martin Sheen, Jamie Lee Curtis, and Brad Pitt in a performance of Dustin Lance Black's play, 8 — a staged reenactment of the federal trial that overturned California's Prop 8 ban on same-sex marriage — as Maggie Gallagher. The production was held at the Wilshire Ebell Theatre and broadcast on YouTube to raise money for the American Foundation for Equal Rights.