Brett Gelman

In 2010, Gelman appeared as a cast member on the Comedy Central sketch comedy special This Show Will Get You High, created by Matt Besser. Gelman co-starred as "Mr. K" on the NBC comedy series Go On starring Matthew Perry, and as A.J. on the FX comedy series Married.

Gelman makes frequent appearances on the Comedy Bang! Bang! podcast, as well as other podcasts on the Earwolf podcasting network. In 2011, he began his own podcast, Gelmania, also available on the Earwolf network. Gelman has said he wanted his podcast to "reflect a lot of the fears and anger and sadness of the world, but do that through a really stupid lens." In 2014, Gelmania began its second season but is no longer on the Earwolf network.

In 2014, Gelman hosted a dinner party special called Dinner with Friends with Brett Gelman and Friends, that aired on Adult Swim.

In 2015, Gelman was also a consulting writer on season two of the entertainment news parody series Hot Package on Adult Swim and also recurs as Hamish on the Comedy Central series Another Period and as Ronnie on the Starz series Blunt Talk. Also in 2015, Gelman appeared in the last season of Mad Men.

In December 2015, Gelman married his long-time girlfriend, writer and director Janicza Bravo. Gelman and Bravo met in New York City while working on a New York Lotto commercial. They divorced in 2019.

In July 2016, Gelman starred in the special Dinner in America with Brett Gelman, a sequel to Dinner with Friends with Brett Gelman and Friends, which focused on racism. In November 2016, Gelman said that he had left Adult Swim due to the network's alleged poor treatment of female employees and the promotion of controversial Million Dollar Extreme Presents: World Peace.

In 2017, Gelman starred in and co-wrote Lemon, opposite Judy Greer, Michael Cera, Nia Long and Gillian Jacobs, directed by Janicza Bravo. It had its world premiere at the Sundance Film Festival on January 22, 2017.

In 2017, it was announced that Gelman was cast in the second season of the hit Netflix science-fiction web series Stranger Things as Murray Bauman, a conspiracy theorist and former journalist. From the fourth season he belongs to the main cast.

In 2018, he starred in the independent feature film Room for Rent, opposite Mark Little, Carla Gallo, Stephnie Weir, Patrick J. Adams, and Mark McKinney. Gunpowder & Sky released the film in the US on all major VOD platforms November 2, 2018.