He also played the recurring roles of Stu on Curb Your Enthusiasm, Jake Steiner on Grey's Anatomy, Ken on Veep, Gabriel on Californication, A. Elliott Stemple on Suits, Dr. Davis Bannercheck on Silicon Valley, Wade Shelton on Shameless, Isaac Heller on Once Upon a Time, Duncan Todd on Twin Peaks, Dan Rifkin on Defending Jacob, and Lon O'Neil on Barry.

His father, Bill, bought a restaurant on the Pacific Coast Highway in Santa Monica, California, while Fischler was five years old, and named it "Patrick's Roadhouse" after him.

[3] In 1998, Fischler starred in the independent film The Week That Girl Died, a romantic comedy about three long-time friends in a small New England fishing town.

[3] and The Great Buck Howard (2008),[10] and portrayed Ellis Loew in Brian De Palma's 2006 crime film The Black Dahlia.

[3] Fischler auditioned for the role of insult comic Jimmy Barrett on the AMC drama series Mad Men, of which he was a fan.

[13] The character, Jimmy Barrett, appears in television ads for a client of the advertising company within the show, and his wife Bobbie sleeps with protagonist Don Draper.

[14] Series creator and executive producer Matthew Weiner cast Fischler because he felt the actor had a "New York quality" that he wanted the character to have.

Fischler called receiving that script "the highlight of my career so far",[4] adding: "After Mad Men I got a lot of 'How dare you speak to Don Draper like that?

[4] On Southland he played Detective Kenny No-Gun;[12] series creator Ann Biderman described him as a "brilliant, incredibly versatile actor".

The game's casting directors worked on Mad Men and specifically approached Fischler for the Cohen character, and he accepted because he likes the film noir genre.

In January 2012, Fischler appeared in One for the Money, a crime thriller film adapted from the 1994 novel of the same name by Janet Evanovich, the first in a series featuring bounty hunter Stephanie Plum.

[18] He portrayed poet Lew Welch in the 2013 Michael Polish film Big Sur, based on the autobiographical novel by Jack Kerouac.