In 1985, while Too Close For Comfort was being retooled as The Ted Knight Show, Bullock learned that he was HIV positive. He made his diagnosis public 11 years later.

After ALF went off the air in 1990, Bullock remained active with theatre, television, and film work. He briefly hosted a syndicated talk show with ex-televangelist Tammy Faye Messner. The Jim J. and Tammy Faye Show debuted in 1996, but Messner exited the program a few months later following a cancer diagnosis. Bullock continued with new co-host, Ann Abernathy, and the show became The Jim J. and Ann Show until it was canceled.

In 1996, Bullock's partner of six years, John Casey, died from AIDS-related complications. Bullock is a longtime survivor of the virus and, as of 2020, was still healthy due in part to antiretroviral drugs.

On February 17, 1999, Bullock was arrested outside a bar in West Hollywood, California, for possession of crystal meth, and was sentenced to probation.

Bullock was the voice of Queer Duck in the animated series of cartoons of the same name which have appeared on both the internet and the cable TV network Showtime. In 2000, Bullock was a regular panelist on the revival of I've Got a Secret. He also performed on the national tour of the Broadway production Hairspray as Wilbur Turnblad, a role he took to the Broadway stage starting September 18, 2007. Some of his other noteworthy roles include the pilled-up narcoleptic Prince Valium in the 1987 Mel Brooks movie Spaceballs, and the "Not-Quite-Out-of-the-Closet" character in the date montage at the beginning of 2001's Kissing Jessica Stein. From 2004 to 2007, he had a recurring role as Mr. Monroe, a teacher at the fictional James K. Polk Middle School on the Nickelodeon live action sitcom Ned's Declassified School Survival Guide.

As of 2020 he was living in Rancho Cucamonga, California.