He is best known for his starring roles in the comedy series MADtv (2002–2007), Eastbound & Down (2012), The Mindy Project (2012–2017), Bless the Harts (2019–2021), The Afterparty (2022), and History of the World, Part II (2023).

On February 2, 2023, he won the inaugural primetime season of Celebrity Jeopardy!, winning $1,000,000 for charity, Pacific Clinics, and placed as a semifinalist in the 2024 Tournament of Champions.

On August 14, 2024, he and his father, Alan, became the first duo and the second celebrities overall to win the $1,000,000 top prize for their charity, the ASL Program at Los Encinos School, and the fifteenth overall million dollar winners on Who Wants to Be a Millionaire.

Barinholtz spent two years in Amsterdam with the famed comedy troupe Boom Chicago along with Jordan Peele, Josh Meyers, and Nicole Parker.

[9] He is a founding member of The Lindbergh Babies, an improv group directed by Del Close, who worked with John Belushi, Bill Murray, Mike Myers, and Chris Farley.

In 2012, Barinholtz joined the cast of the third season of the HBO series Eastbound & Down, playing the role of Ivan Dochenko, Kenny Powers' Russian rival.

[11] Barinholtz appeared in a regular role as nurse Morgan Tookers on the comedy series The Mindy Project.

Barinholtz often paired up with fellow cast member Josh Meyers in various sketches for the eighth and ninth seasons similar to the Mike Myers/Dana Carvey and Jimmy Fallon/Horatio Sanz duos on Saturday Night Live.

Some of his famous characters included Abercrombie & Fitch model Dutch and Principal Lankenstein from the Coach Hines sketches.

Barinholtz's celebrity impressions included Abraham Lincoln, Alex Trebek, Andy Dick, Arnold Schwarzenegger, Ashton Kutcher, Bo Bice, Dane Cook, Felicity Huffman, Fidel Castro, George Michael, Howard Dean, Howie Long, Kevin Federline, Mark Wahlberg, Clay Aiken, Matt Damon, Nick Lachey, Nick Nolte, Pat Sajak, Ralph Nader, Rafael Palmeiro, and Vin Diesel.