Born in Syria, his family immigrated to the United States when he was two years old. He originally wanted to be a physician but developed a passion for acting when he began acting classes to overcome his shyness.

It was the popular TV series, Broken Arrow (1956) where he played the lead role of Cochise which raised his profile and made him a household name on TV.

Whilst making the series the 20th Century Fox Publicity Department arranged a date between himself and actress Barbara Eden. The two later married and he guest starred on the I Dream of Jeannie series (where his wife played the lead role). They had one son together, actor Matthew Ansara, who died on June 25, 2001 after a heroin overdose.

Michael Ansara and Barbara Eden divorced in 1974. He is now semi-retired.

In recent years he is perhaps best known as the voice of Mr. Freeze in Batman: The Animated Series.

Along with Jonathan Frakes, Marina Sirtis, Armin Shimerman, John de Lancie and Richard Poe, he is one of only six actors to play the same character on three different Star Trek series. He played Kang in Star Trek: The Original Series, Star Trek: Deep Space Nine and Star Trek: Voyager. He also provided the voice of Q's supervisor in the Next Generation episode True Q and played Lwaxana Troi's husband Jeyal on the Deep Space Nine episode The Muse.

He played the "Technomage" Elric in the sci-fi series Babylon 5, and "Killer Kane" in the 1979-1980 season of Buck Rogers in the 25th Century . He also played two different characters in two episodes of the 1966 Sci-Fi TV series “Time Tunnel”. In episode #11 he played Colonel Hruda and in episode#28 he played the Curator.