His also had film roles in Monte Walsh (1970), The Andromeda Strain (1971), Johnny Got His Gun (1971), The Last Tycoon (1976), An Enemy of the People (1978), Attack of the Killer Tomatoes (1978), The Changeling (1980), Middle Age Crazy (1980), The Philadelphia Experiment (1984), and All of Me (1984).

He also appeared in the episode, "When I'm 64", in the TV series ALF as Bernie, one of the residents of a retirement home, Bugsy (1991), Almost Dead (1994), Air Bud (1997), and his final feature film Mouse Hunt (1997).

Christmas also made guest appearances on many television shows, including Columbo (as a sardonic Jeweler in "A Friend in Deed"), Adventures in Rainbow Country, Due South, ER, Misfits of Science, Night Court, The Fresh Prince of Bel-Air, Wiseguy (as Harry "The Hunch" Shanstra), Seinfeld (as Jeffrey Haarwood in "The Gum"—Episode 120, first airing on 14 December 1995), Cheers (season 7; episode 2), Home Improvement (as Sir Larry the Magician), Coach (as Brian Currie), The Golden Palace, The X-Files, Booker, Matlock, Walker Texas Ranger, Roseanne, L.A. Law (as Buzz Carr), Major Dad, Ally McBealand Amen.

He went to San Diego to teach and to help revive the La Jolla Playhouse, for which he directed The Man Who Came to Dinner in temporary space at La Jolla High School, with equity actor Larry Seaman in the lead role, and also starring Robert Zimmerman (BHP-San Francisco Faculty) as the reporter and James Pearson as Banjo.

In 1983 Christmas played and sang the role of "Jack Point" in the San Diego Gilbert and Sullivan Repertory Company's production of The Yeomen of the Guard.