Kathryn McKinnon Berthold (born January 6, 1984) is an American actress, comedian and writer. She is known for her character work and celebrity impressions on the sketch comedy series The Big Gay Sketch Show (2007–2010) and Saturday Night Live (2012–present). McKinnon has appeared in films such as Balls Out (2014), Ghostbusters (2016), Office Christmas Party (2016), Rough Night (2017), The Spy Who Dumped Me (2018), Yesterday (2019), and Bombshell (2019).

McKinnon has been nominated for seven Primetime Emmy Awards, including one for Outstanding Original Music and Lyrics and six for Outstanding Supporting Actress in a Comedy Series, winning in 2016 and 2017.

McKinnon was born and raised in the Long Island town of Sea Cliff, New York, to Laura Campbell, a parent educator, and Michael Thomas Berthold, an architect. She has a younger sister, comedian Emily Lynne, whom she has collaborated with before on the Audible series, Heads Will Roll, as well as digital series, “Notary Publix”. Her father died when she was 18 years old. She is of German and Scottish descent.

As a child, McKinnon played several instruments. She started playing the piano when she was five years old, the cello when she was 12, and taught herself how to play the guitar when she was 15.

McKinnon's knack for accents began when she was in fifth grade. She auditioned to be "the queen of reading week" and used an English accent. In an interview with Rolling Stone, she says, "I think the genesis of my entire life, probably, was the smiles I elicited doing this British accent. I've been chasing that dragon ever since."

She graduated from North Shore High School in 2002, and from Columbia University in 2006 with a degree in theatre, where she co-founded a comedy group, Tea Party, which focused on musical improv comedy. At Columbia, she starred in three Varsity shows: V109 "Dial D for Deadline", V110 "Off-Broadway" and V111 "The Sound of Muses". She was also a member of Prangstgrüp, a student comedy group which set up and recorded elaborate college pranks.

In 2007, McKinnon joined the original cast of Logo TV's The Big Gay Sketch Show, where she was a cast member for all three seasons.

Since 2008, she has performed live sketch comedy regularly at the Upright Citizens Brigade Theatre in New York City. She has also worked as a voice-over actress, and has voiced characters for series such as The Venture Bros., Robotomy, and Ugly Americans. In 2009, McKinnon won a Logo NewNowNext Award for Best Rising Comic. She was nominated for an ECNY Emerging Comic Award in 2010. In 2014, she appeared in the Kennedy Center Honors as part of a tribute to Lily Tomlin. In 2016, she starred in the reboot Ghostbusters, alongside Melissa McCarthy, and fellow SNL cast members Kristen Wiig and Leslie Jones. In 2017, McKinnon is attached to star in Amblin Entertainment's Lunch Witch, an adaptation of a young adult graphic novel by Deb Lucke. She has been set to play the title role of Grunhilda, an out-of-work witch who takes a job in a school cafeteria to make ends meet.

McKinnon has made appearances as a voice actress in series like The Simpsons (as Hettie in season 27, episode 14 "Gal of Constant Sorrow") and Family Guy (a voice in season 14, episode 15 "An App a Day", as Karen / Heavy Flo in season 14, episode 6 "Peter's Sister", and a voice in season 15, episode 9 "How the Griffin Stole Christmas"), and films such as Finding Dory (as Stan's fish wife), The Angry Birds Movie (as Stella / Eva the Birthday Mom) and Ferdinand (as Lupe). McKinnon currently voices the character of Ms. Frizzle in the reboot of the Magic School Bus children's series. McKinnon also voices Squeeks the Mouse In The PBS Kids TV Series Nature Cat.

McKinnon is known for her character work and celebrity impressions of pop singer Justin Bieber, comedian television host Ellen DeGeneres, and numerous political figures, including Hillary Clinton, US Attorney General Jeff Sessions, Senator Lindsey Graham, Supreme Court Justice Ruth Bader Ginsburg, Senator Elizabeth Warren, Kellyanne Conway, Robert Mueller, Angela Merkel, and Rudy Giuliani. She has been nominated for seven Primetime Emmy Awards, including one for Outstanding Original Music and Lyrics and six for Outstanding Supporting Actress in a Comedy Series, winning in 2016 and 2017.

McKinnon debuted as a featured player on Saturday Night Live on April 7, 2012. She was promoted to repertory status in season 39 in 2013. Following Vanessa Bayer's departure, McKinnon is now the longest serving female cast member. She also surpassed Bayer as the longest serving female performer in history when on May 4, 2019, McKinnon entered her 150th episode as a cast member, compared to Bayer's 149 episodes. As of April 2020, she has been a cast member for 169 episodes.

In 2013, McKinnon was nominated for an Emmy Award for Best Supporting Actress, Comedy. McKinnon won the 2014 American Comedy Award for Best Supporting Actress, TV for her work on SNL. In 2014, she was nominated for an Emmy Award for Outstanding Supporting Actress in a Comedy Series, as well as for Outstanding Original Music and Lyrics along with four of her colleagues for the song "(Do It On My) Twin Bed". She was nominated for an Emmy for Outstanding Supporting Actress in a Comedy Series for the second time in 2015. She won the following next year, becoming the first actor from SNL to win the award since Dana Carvey in 1993.

McKinnon began appearing as Hillary Clinton on the series leading up to the 2016 presidential election. The real Clinton appeared alongside her in a sketch during the show's season 41 premiere. McKinnon has said that her impression of Hillary Clinton comes from a deep admiration, and that she "unequivocally want her to win" the 2016 presidential election. On November 12, 2016, which was the first show after Clinton's loss in the election, she reprised the role to open the show with a solo performance of "Hallelujah" by Leonard Cohen, whose death was announced two days before her performance. After the election, McKinnon began to impersonate Kellyanne Conway alongside Alec Baldwin as Donald Trump. On February 11, 2017, she debuted her impression of Elizabeth Warren during Weekend Update and Jeff Sessions in the cold open.