She was a cast member on the NBC sketch comedy series Saturday Night Live from 2012 to 2022, where she became known for her character work and celebrity impressions.

[3][1] McKinnon has also appeared in numerous films, such as Sisters (2015), Office Christmas Party (2016), Rough Night (2017), The Spy Who Dumped Me (2018), Yesterday (2019), The Bubble (2022), and Barbie (2023).

McKinnon was born and raised on Long Island in the town of Sea Cliff, New York,[1][4] to Laura Campbell, a parent educator, and Michael Thomas Berthold, an architect.

[1][12][13] Her cast and crewmates included future actors Jenny Slate and Grace Parra, directors Tze Chun and Greta Gerwig, and The Onion managing editor Peter Koechley.

In 2016, she starred in the reboot Ghostbusters, alongside Melissa McCarthy, and fellow SNL cast members Kristen Wiig and Leslie Jones.

McKinnon has made appearances as a voice actress in series like The Simpsons (as Hettie in "Gal of Constant Sorrow") and Family Guy (as Karen / Heavy Flo in season 14, episode 6 "Peter's Sister", and additional voices in other episodes), and films such as Finding Dory, The Angry Birds Movie, Ferdinand and DC League of Super-Pets.

[23] Since 2015, she has voiced Squeeks in the PBS Kids series Nature Cat, starring with fellow SNL cast members Taran Killam and Bobby Moynihan.

McKinnon joined the cast of Saturday Night Live as a featured player on April 7, 2012, following a March 28, 2012 report of her being hired.

McKinnon is known for her character work[18] and celebrity impressions[39] of pop singer Justin Bieber, comedian television host Ellen DeGeneres, and numerous political figures, including US Attorney General Jeff Sessions, Senator Lindsey Graham, Supreme Court Justice Ruth Bader Ginsburg, Clinton, Warren, Robert Mueller, Angela Merkel, and Rudy Giuliani.

[50] McKinnon and Lynne also created and released the fantasy-comedy Audible audio series Heads Will Roll, which premiered in May 2019.

[7] The show features guest appearances from Meryl Streep, Peter Dinklage, Audra McDonald, Bob the Drag Queen, Queer Eye's Fab Five, and Tim Gunn.

Additionally, many of McKinnon's SNL co-stars are featured, including Aidy Bryant, Alex Moffat, Heidi Gardner and Chris Redd.

The work would focus on events among three sisters from the Porch family and the mad scientist in the fictional town of Antiquarium.

[62][63] Nino appeared in a "Whiskers R We" sketch filmed from McKinnon's home in response to the COVID-19 pandemic, playing the role of all the cats up for adoption.