[5] As an actress, Firestone has appeared in the TV programs Search Party, The Jim Gaffigan Show, Broad City, The Tonight Show Starring Jimmy Fallon, CollegeHumor Originals, Boy Band, The Outs, Night Train with Wyatt Cenac, Animal Agent, High Maintenance, Jon Glaser Loves Gear, Thanksgiving, The Special Without Brett Davis, Shrill, and others.

She has also performed on the Tonight Show, portraying U.S. Education Secretary Betsy DeVos,[7] demonstrating products from the New York Toy Fair,[8] and appearing in other sketches opposite host Jimmy Fallon.

[9] Firestone portrayed the character Sarah Conner, a band teacher, on Joe Pera Talks with You, which aired during Adult Swim on Cartoon Network.

[13] With Dylan Marron, Firestone wrote, performed in, and directed Ridgefield Middle School Talent Nite,[14] which received a Capital Fringe Festival Director's Award in 2010.

"[18] Firestone is the host of the program Dr. Gameshow, which originated on WFMU radio and is now a podcast on the Maximum Fun network along with co-host Manolo Moreno.

[24] Everyday Decisions is a comedy and personal stories podcast where Firestone interviews friends, family, and fellow comedians about the past 24 hours of their day.