Richard Paul was Jerry Falwell in the TV movie about the Bakkers “Fall From Grace” and in “The People Vs. Larry Flynt”.
Way back when he was the Mayor in “Carter Country”, Dad said that if there was ever a show with Falwell as a character, RP’s be a perfect fit.
Richard Paul also played a very Falwell-like character in an episode of WKRP in Cincinnatti.
My favorite was Carl Reiner’s appearance as Alan Brady on “Mad About You”.
This is a bit off-topic, but what the hell…
According to IMDB, Susannah Harker, the actress who played vampire hunter Angela Marsh in the British TV serial Ultraviolet, is actually a descendant of the real-life Jonathon Harker, a friend of Bram Stoker, who was immortalized in Stoker’s novel “Dracula”.
Kinda neat. (If you haven’t seen this serial, do so.)
In addition to “The Beverly Hillbillies,” Irene Ryan played “Granny” in “Petticoat Junction,” “Mr. Ed,” and the movie “Don’t Worry, We’ll Think of a Title.”
Bobby Watson played Hitler a bunch of times.
Andrew Duggan played Ike three times. (He was also married IRL to the cutie seen running along the beach and turning to the camera in the opening credits of “Hawaii Five-O”
Bryan Clark played Ronald Reagan four times.
But with the same writer/director, those are practically sequels! 
Speaking of Sheens, Martin played both Jack and Bobby Kennedy. CLOSE!
Bumped.
Gary Lydon played Gerry, an Irish beat cop, in the 2000 short film The Second Death. He played Insp. Gerry Stanton - clearly the same character, moved up in the ranks - in the 2011 dark comedy The Guard, and again in the religious drama Calvary in 2014. (Brendan Gleeson was also in the latter two movies, as another cop in The Guard, and as a priest in Calvary). The movies are very different, but have some shared elements and actors - all are worth a look.
Prior to Det. Munch being the superglue that holds the entire universe together, David Clennon played “Miles Drentell” in* thirtysomething *and then later in the show Once and Again.
Though created by the same people, I don’t think the two shows are meant to be related, like a spin off or something.
Jerry Haleva has played Saddam Hussein 5 or 6 times in movies. In fact, it’s the only part IMDB shows him playing.
Will Jordan has played Ed Sullivan in a whole bunch of really big shooos
William Daniels played John Quincey Adams in 1954 and again in 1976-1981 – a 24-29 year stretch. He didn’t play that Adams in between, but he was more famously John Adams more than once, and Sam Adams.
Ian Holm played Napoleon Bonaparte in the TV miniseries Napoleon in Love in 1975 and in the film Time Bandits in 1981.
See post 17.
Bob Hoskins played Smee in both the Robin Williams movie Hook and the unrelated (other than from the same source material, duh) Syfy miniseries Neverland.
And I could swear I posted that same factoid in a very similar topic here a few months ago.
Shortly before he died, Herrmann also read all of FDR’s lines in Ken Burns’ The Roosevelts.
Christopher Lloyd played Doc Brown in the Back to the Future Trilogy and in a cameo appearance in A Million Ways to Die in the West.
Bumped.
Just saw Six Shooter, the 2004 Oscar winner for Short Film, and there’s Lydon, once again as an Irish cop (listed in the credits only as “Chief Guard”). He’s like the Irish Dennis Franz.
as I’ve remarked in the past, several actors reprised their roles in remakes of their own originals
Jimmy Stewart played Elwood P. Dowd in both the original movie Harvey and its later TV remake
Clark Gable played the same role in Red Dust and its 1953 remake Mogambo.
Sean Connery played James Bond in Thunderball and its virtual remake Never Say Never Again
Alastair Sim played Ebenezer Scrooge in both the 1951 version of A Christmas Carol and again twenty years later in the Chuck Jones-produced animated TV version.
This is the supposedly complete list of all crossovers in American television. This is all cases where the same actor played the same character in more than one American television series. This is then organized into crossover universes. The largest one is Group 2: