He made an appearance in Star Trek: The Next Generation as Boothby, head groundskeeper at Starfleet Academy in San Francisco, and he reprised the character twice on Star Trek: Voyager, despite the series being set in a distant part of the galaxy. (The first time, he actually played an alien participating in a simulation of the Academy; the second appearance was in a dream sequence.) During his appearance on Voyager in "In the Flesh", he often had trouble with remembering his lines during long one-shot dialogue scenes, but while the cameraman was changing the film for the scene in the briefing room, he quoted a line from Hamlet. Robert Beltran then quoted the next line, and Walston the next. The two went on for several minutes, amazing the entire cast and crew. In a twist of fate Beltran had starred in the role of Luther Billis while in high school [11]
In 1985, Walston made a brief appearance in the opening credits of Steven Spielberg's series Amazing Stories, as a caveman acting out a story for his tribe. Only a few seconds long, this performance began every episode of the subsequent series. In 1988, he guest starred in an episode of the popular horror-fantasy show Friday the 13th: the Series, as a bitter, elderly comic-book artist who uses a demonically cursed comic book to transform himself into a killer robot and murder his erstwhile enemies. In 1992, Walston played the role of Candy in the big-screen remake of John Steinbeck's Of Mice and Men with Gary Sinise and John Malkovich. He would work alongside Sinise again two years later in the miniseries adaptation of Stephen King's The Stand.[12]
Walston was nominated three times for Best Supporting Actor in a Drama Series for his work on Picket Fences, winning twice, in 1995 and 1996. CBS cancelled the show after four seasons in 1996. Walston made a guest appearance in an episode of Dr. Quinn, Medicine Woman entitled "Remember Me", in which he portrayed the father of Jake Slicker, who was stricken with Alzheimer's disease.