Law & Order Guest Roles We're Glad Turned Into Permanent Gigs

If "Law & Order" was a person, it could legally drink in the U.S. Debuting in 1990, "Law & Order" ran for 20 seasons and the revival in 2022 makes Season 21. It was the original in the "Law & Order" franchise that was followed by the wildly popular "Law & Order: SVU" and the most recent "Law & Order: Organized Crime." The 2022 revival is bringing back familiar faces from the original: Sam Waterston, who played D.A. Jack McCoy, and Anthony Anderson, who played Detective Kevin Bernard.

The New York City based police procedural has had its fair share of memorable and now famous guest stars over the years. According to Entertainment Weekly, Sarah Paulson, who you may know from "Ocean's 8" or "American Horror Story," played a 14-year-old on "Law & Order" for her first onscreen credit. Philip Seymour Hoffman also got his first acting credit with a 1991 episode.

Some guest stars just couldn't stay away and ended up as regulars on the show.

S. Epatha Merkerson first appeared on "Law & Order" in 1991 as Mrs. Denise Winters in the episode "Mushrooms." The next time she was on the show, it was as Lieutenant Anita Van Buren in 1993, and she had that role for 16 years (via Entertainment Weekly). When she left, she told EW that, "It's a graceful way to go. It's the end of my contract this year, and the storyline has been so perfect. I've given it my best for 16 years. It's time to move on." She's now on "Chicago Med" with no plans to return to the "Law & Order" reboot (via Deadline).

Another longtime "Law & Order" actor had a similar situation. Jerry Orbach played NYPD Detective Lennie Briscoe for 12 years, but before he was the wise-cracking Briscoe, Orbach had a guest spot in Season 2 as Defense Attorney Frank Lehrman.

Jeremy Sisto was introduced in Season 18 of "Law & Order" as Detective Cyrus Lupo. "It's a different kind of acting, this 'Law & Order' thing," he told Today in 2007. "This is a very specific gig." But it wasn't his first time on set. He played lawyer Clint Glover in the Season 17 finale.

Other guest stars on "Law & Order" ended up on one of the spin-off shows.

Courtney B. Vance has more recently played famous lawyer Johnnie Cochran in "American Crime Story: The People vs OJ Simpson" (via ABC News). However, it wasn't his first time portraying a lawyer. He was ADA Ron Carver on "Law & Order: Criminal Intent" for five years and over 100 episodes starting in 2001. But according to IMDb, he first showed up in 1990 on "Law & Order" as an unnamed mayor's assistant, and then again in 1995 as Benjamin "Bud" Greer.

Tamara Tunie, who plays Medical Examiner Melinda Warner on "Law & Order: SVU," first started in the "Law & Order" franchise in 1996 with a guest role playing Caroline Bennette in the episode "Deadbeat." According to TV Insider, Tunie was a series regular on "Law & Order: SVU" from Seasons 7 to 12 and she appeared again for some cameo appearances in Season 21 and 22. She has hinted that her character could make an appearance on "Law & Order: Criminal Intent" (per PopCulture).

A couple more "Law & Order: SVU" stars also got their start on "Law & Order."

Raúl Esparza played ADA Rafael Barba on "Law & Order: SVU," helping Mariska Hargitay's character Olivia Benson put away sex offenders from Seasons 14 to 19, and then returning in a dramatic cameo in Season 22 in crossover episode for "Law & Order: SVU" and "Law & Order: Criminal Intent" (per TV Insider). However, Esparza was on the other side of the law in a 2010 "Law & Order" episode, playing blackmailer Dennis di Palma in the aptly named episode "Blackmail."

Then there's Peter Scanavino who first showed up as a guest star of "Law & Order" as Jim Anderson in a 2009 episode. Scanavino has gone on to feature as Detective Dominick "Sonny" Carisi Jr. and then ADA Carisi on "Law & Order: SVU." Of his role changing from detective to ADA in Season 21, Scanavino told TV Insider, "[Carisi's] job is to uphold the law, and he knows that supersedes any personal opinion he has on an issue. You can see the internal conflict in Carisi, but at the end of the day, he's an officer of the law."