Can prison be counted as a “previous role”?
In the movie, “Expendables 3”, the Expendables break a fellow team member, Doc, out of prison because they need him for their difficult mission ahead. The team member, Doc, who was sprung from prison is played by Wesley Snipes. One of the new team members asked Doc why he was in prison. Doc replied, “Income tax evasion”.
In a slight departure from the OP’s request, George Lazenby made an allusion to a previous actor in the SAME role when he took over the 007 franchise from Sean Connery. When the Girl drives off and leaves him by himself on the beach (“On Her Majesty’s Secret Service”), he quips “This never happened to the other fellow”.
A whole episode of Scrubs.
In one of the Netflix seasons of Arrested Development there’s a scene where George Bluth Sr. was trying to evade the authorities by disguising himself as a woman or something like that (I don’t remember the exact context anymore). Then he realizes that is a bad plan, as the narrator says something like “Realizing he was never going to win an Emmy for playing a woman…”, pretty obviously referencing Jeffrey Tambor’s Emmy for his other role on Transparent.
Most of the ones that come immediately to mind have already been covered.
One case where they missed a golden opportunity for this (according to my wife, Pepper Mill, who’s a big Scott Bakula fan) was when, at the end of the first episode of Star Trek: Enterprise they finally get the transporter working and successfully beam Bakula (as Jonathan Archer) out.
It would have been perfect if, upon resolidifying, he then said “Ohhh, boy!”, the inevitable line used by Bakula as Sam Beckett in Quantum Leap after “leaping” into another body.
On Andromeda, Capt. Dylan Hunt finds the sword of Hercules in a storage nook.
Andromeda Hercules reference - YouTube
In Santa Clause 2 Tim Allen playing the robot Santa yells at Tim Allen playing the real Santa “you are a sad strange little man”.
Same line Tim Allen delivered as Buzz Lightyear to Cowboy Woody.
In another episode, Jane Curtin’s character is watching television and the announcer says “Up next, the Susan Saint James story” to which Curtin dismissively snorts and says “Who’d want to watch that?” before changing the channel.
Jane Curtin and Susan Saint James having been co-stars on Kate & Allie.
And, in said movie (Toy Story), when Buzz and Woody are trapped in Sid’s bedroom, Woody is stuck in a milk crate, under a Binford toolbox. Binford was the fictional tool company which sponsored “Tool Time,” the television series hosted by Tim Taylor (Tim Allen) on Home Improvement.
Also on Arrested Development, this woman (who I’m gonna call Trixie because I can’t remember her name) shouts an angry parting shot at Michael Bluth, and calls him “Opie.” Narrator Ron Howard comments: “Trixie had gone too far. And she had best watch her mouth.”
Speaking of Tim Allen, one of those ending social media commercials in “Last Man Standing” had his character Mike searching for an alternative to “winning is everything”. Kyle suggests “Never give up. Never surrender.”
Mike really likes this, repeats it, then does the salute.
Hmm, I never felt a particular desire to see Paul, but if Blythe Danner is in it I may have to seek it out.
I think there was also an episode of 3rd Rock where Mary (Jane Curtin) and Dick went to a sci-fi convention and Mary saw a couple cosplayers dressed as coneheads. Jane, of course, was the original Prymaat on SNL.
In Star Trek VI Spock says
Leonard Nimoy never played Holmes onscreen, but he did play The Great Detective on stage in the William Gillette play Sherlock Holmes in 1976
https://fanlore.org/wiki/Sherlock_Holmes_(1976_play)
Holmes uses a variation of the line in The Sign of Four, but I think it’s in the Gillette play, which is cobbled together from several Holmes stories. It’s been too long since I saw or read it.
In the Futurama episode A Bicyclops Build For Two, Leela, voiced by Katey Segal, calls her fiance Alcazar “Al” and dresses like Peggy Bundy in an attempt to keep him happy, resulting in a scene that parodies the sitcom Married With Children. Katey Segal played Peggy on Married With Children.
Nathan goes nuts at Super Nova Con:
Not only dropping a line or three from Firefly, but referencing Whedon and taking a shot at the director of the episode, who is the guy getting an autograph at the start of the clip.
At the end of Doc Hollywood Michael J Fox meets up with Woody Harrelson’s character and Bridget Fonda’s character at a restaurant in LA (Beverly Hills). Bridget Fonda’s character is all excited about seeing celebrities. At the every end of the scene (camera is on Fox, so you only hear the dialogue), Fonda asks “Is that a star ?”. And Harrelson’s character replies, “No. That’s Ted Danson”.
A nice jab at his “Cheers” co-star.
Eight Simple Rules did a good portion of one episode parodying Three’s Company, John Ritter’s earlier show, as a dream sequence. It was very funny.
And for good measure, the final scene has John Ritter waking up in bed next to Don Knotts. (Yes, that was also a dream.)
And let’s not forget the scene in Stay Tuned where John Ritter’s character is zapped into an episode of Three’s Company.
Mary Tyler Moore hosted a show, Mary, after her sitcom ended. Dick van Dyke was a guest and they did skits about Rob and Laura. The topper was when she met Van Dyke at the end and said she had auditioned for the show, but Rose Marie got the part.
Boston Legal is rife with subtle digs at Star Trek and TJ Hooker–both Shatner platforms.