It says a lot about how successful SNL alumni are that many of them have been made fun of on the show after leaving. Ever since the show's ex-cast members first started to go out on their own in the late '70s/early '80s, many of them have become as well-known as the celebrities SNL regularly mocks, and in the '90s, the show stopped shying away from showcasing impressions of their better known alumni.
From Dana Carvey's Dennis Miller to Jimmy Fallon's Chris Rock, here's a list of times SNL cast members have played other SNL cast members on the show:
1. Paul Shaffer – played by Gary Kroeger (1982-1983), Mark McKinney (1997), and Chris Kattan (1997)
It's hard to do a Letterman sketch without his bandleader Paul Shaffer, who played piano in SNL's house band during the 1970s and was briefly a featured player from 1979 to 1980. Gary Kroeger played Paul Shaffer to Joe Piscopo's David Letterman, while Mark McKinney and later Chris Kattan were the Shaffer to Norm Macdonald's Letterman.
2. Dennis Miller – played by Dana Carvey (1987-1992) and Jimmy Fallon (2000, 2001)
One of the few SNL cast members to be impersonated while he was still on the show, Dennis Miller was frequently joined at the Weekend Update desk by Dana Carvey doing an impression of him. Later, during Miller's brief stint as an NFL color commentator in the early 2000s, Jimmy Fallon played him. Non-cast member but frequent Tom Hanks also got in on making fun of Dennis Miller in this memorable sketch in which he played Miller alongside Carvey and the real Dennis Miller in 1990:
3. Billy Crystal – played by Rob Schneider (1992)
Rob Schneider did a pretty solid impression of Billy Crystal, who had a short stint on SNL from 1984 to 1985. Schneider only did the impression one time in a sketch called "The First Annual Gutenbergs" that saw then-frequent Oscar host Billy Crystal hosting the Oscars for books, complete with a medley of book-related songs at the top of the ceremony.
4. Eddie Murphy – played by Chris Rock (1993), Tim Meadows (1997), and Jay Pharoah (2010, 2011)
Eddie Murphy is one of the most frequently-portrayed former cast member, and it's not hard to see why as he's had one of the most successful and longest post-SNL careers. Rock played Murphy in a commercial for a black version of Indecent Proposal called "Ignorant Proposal" that also starred Tim Meadows as Billy Dee Williams and Ellen Cleghorne as Mary J. Blige. Meadows played him in a sketch called "Eddie Murphy: Good Samaritan," goofing on a tabloid story about Murphy getting pulled over with a transsexual prostitute, and Pharoah has played him in a couple sketches, most notably an '80s Eddie Murphy in the Back to the Future auditions sketch:
5. Jon Lovitz – played by Darrell Hammond (1996)
In one of Molly Shannon's earliest "Mary Katherine Gallagher" sketches, she was auditioning for a teen modeling contest judged by Jon Lovitz (played by Darrell Hammond). Hammond only did the impression one time, and the sketch is pretty hard to track down.
6. David Spade – played by Chris Kattan (1997)
David Spade had only been off of SNL for one season when Chris Kattan played him in one of Jim Breuer's Joe Pesci Show sketches. Kattan's Spade angered Pesci so much that he and sidekick Robert DeNiro (Colin Quinn) beat him up with baseball bats, and the sketch memorably ended with the real Pesci and DeNiro coming out and beating the fake ones up with baseball bats.
7. Gilbert Gottfried – played by Jimmy Fallon (1998, 2003) and Taran Killam (2010)
Jimmy Fallon played Gilbert Gottfried in a Hollywood Squares parody and a celebrity reality show parody, while Taran Killam played the nasal-voiced comedian auditioning for the part of Biff in the show's Back to the Future audition tapes sketch.
8. Chris Rock – played by Jimmy Fallon (2000) and Jay Pharoah (2011)
Jimmy Fallon does an excellent Chris Rock impression but only did it once on the show, auditioning to be Regis Philbin's (Darrell Hammond) new co-host after Kathie Lee Gifford left his show. Jay Pharoah played Rock a couple years ago in a sketch called "Rock's Way" that saw Rock debuting a new Broadway show in which he paid acted out a bunch of other Broadway shows.
9. Janeane Garofalo – played by Rachel Dratch (2000)
Rachel Dratch also did an SNL cast member impression in the above-mentioned Regis Philbin co-host audition sketch, playing Janeane Garofalo, who had a short stint on SNLfrom 1994 to 1995.
10. Julia Louis-Dreyfus – played by Michaela Watkins (2009)
In a talk show sketch called "Two First Names," focusing on celebrities with two first names, Michaela Watkins makes an appearance as Julia Louis-Dreyfus, who actually has two last names not two first names but whatever.
11. Joan Cusack – played by Abby Elliott (2009, 2010)
Abby Elliott played Joan Cusack, who was on the show from 1985-1986, in a couple celebrity impression-heavy sketches, most notably the Back to the Future sketch, which is embedded above and also features impressions of '80s SNLers Eddie Murphy and Gilbert Gottfried.
12. Tracy Morgan – played by Jay Pharoah (2013)
Jay Pharoah recently debuted his Tracy Morgan impression on the show in one of those impression showcase sketches. This one, a series of auditions for the 50 Shades of Grey movie, featured a bunch of celebrity pairings including Tracy Morgan and Tilda Swinton.