A guest appearance in Little House on the Prairie impressed producer-star Michael Landon, who cast him in the leading role in the 1978 TV movie Killing Stone.

For the remainder of the 1990s, Gerard made guest appearances on various TV shows, including Fish Police, Brotherly Love, The Big Easy, Days of Our Lives and Pacific Blue.

In January 2007, Gerard was the subject of the one-hour documentary Action Hero Makeover, which was written, produced and directed by his then-longtime companion, Adrienne Crow for the Discovery Health Channel.

[8] By the time of the program's production, his weight had risen to over 350 pounds (159 kg), and he had many life-threatening health issues including a severe problem with type 2 diabetes.

[10] Gerard guest-starred as Admiral Jack Sheehan in "Kitumba", the January 1, 2014, episode of the fan web series Star Trek: Phase II.

Their seven-year marriage began to disintegrate following the cancellation of Gerard's show Buck Rogers in the 25th Century and his increasing addictions to drugs, alcohol, and overeating.

Although he went through recovery for his addiction to cocaine and alcohol, following his divorce from Sellecca in the mid 1980s, his compulsive eating habits increased and he would find himself devouring unhealthy portions of junk food.

By 1988, he weighed 300 lb (136 kg) and used a self-help treatment for his addiction, though he estimated that his weight problem had cost him work opportunities in the region of a million dollars.