He began his career as a stand-up comedian, first entering the national spotlight when he was featured on Billy Crystal's first cable TV special, and went on to become a series regular on ABC's Fridays.

From 1989 to 1998, he played Cosmo Kramer on Seinfeld, three times receiving the Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series.

His film credits include So I Married an Axe Murderer, Airheads, Young Doctors in Love, Problem Child, Coneheads, UHF, and Trial and Error, one of his few starring roles.

After the tape was obtained and released by TMZ,[6] significant backlash and media coverage led to Richards retiring from stand-up in early 2007.

In 2009, he appeared as himself in the seventh season of Curb Your Enthusiasm alongside his fellow Seinfeld cast members for the first time since the show’s finale.

[14] He also had a short-lived improv act with Ed Begley Jr. During this period, he enrolled at Los Angeles Valley College and continued to appear in student productions.

[15] The film Man on the Moon featured a re-enactment of the Andy Kaufman incident where Richards was portrayed by actor Norm Macdonald.

[18] In 1986, Richards had a minor role in the cult satirical TV miniseries Fresno, playing one of a pair of inept criminal henchmen.

That same year he auditioned to play Al Bundy in the TV series Married... with Children, but he was passed over for Ed O'Neill.

[19] In 1989, Richards had a supporting role in "Weird Al" Yankovic's comedy film UHF as janitor Stanley Spadowski.

Elsewhere as a television producer making a documentary about Dr. Mark Craig; in Cheers as a character trying to collect on an old bet with Sam Malone; and made several guest appearances with Jay Leno as an accident-prone fitness expert.

According to an interview with executive producer David Hoberman, ABC first conceived the series Monk as a procedural police comedy with an Inspector Clouseau-like character suffering from obsessive-compulsive disorder.

Richards won more Emmys than any other Seinfeld cast member, taking home the award for Outstanding Supporting Actor in a Comedy Series in 1993, 1994, and 1997 for his role as Kramer.

He also had a cameo role in the comedy thriller film So I Married an Axe Murderer, credited as "insensitive man".

He played radio station employee Doug Beech in Airheads, and co-starred with Jeff Daniels as an actor pretending to be a lawyer in 1997's Trial and Error.

When the first pilot failed with test audiences, NBC ordered that the show be retooled into a more conventional, office-based sitcom before its premiere.

During a performance on November 17, 2006 at the Laugh Factory in Hollywood, California, Richards launched into a racist rant in response to repeated heckling and interruptions from a small group of Black and Hispanic audience members.

And that's how it all started.The incident remained unknown to the larger public for three days until a cellphone video filmed by a member of the audience was obtained and released by TMZ.

A Gallup poll conducted in late November found that only 41 percent of Americans still held a favorable view of Richards.

One year after the incident, Richards voiced character Bud Ditchwater in the animated film Bee Movie, which starred and was produced by Jerry Seinfeld.

In 2019, Richards played Daddy Hogwood in the romantic comedy Faith, Hope & Love starring Peta Murgatroyd and Robert Krantz.