Constantine was born Gus Efstratiou in Reading, Pennsylvania. He was the son of Andromache (née Fotiadou) and Theocharis Ioannides Efstratiou (a steel worker), both immigrants from Greece.3
He began his career on the New York stage in the mid-1950s as understudy to Paul Muni in Inherit the Wind.4
He studied acting with such prominent mentors as Howard Da Silva and played character roles on and off Broadway in his mid-twenties, supplementing his income as a night watchman and shooting-gallery barker. In 1959, he appeared in his first film, The Last Mile (1959). He had a small but memorable supporting role in The Hustler (1961). In 1964 and 1965, Constantine appeared on Perry Mason, first as wannabe private eye Dillard in "The Case of the Blonde Bonanza", and then as Pappy Ryan in "The Case of the Runaway Racer". In 1965, Constantine was cast as the historical John Chisum in the episode "Paid in Full", on the syndicated television anthology series Death Valley Days.5 He also appeared in another 1965 Death Valley Days episode "The Great Turkey War".6 In 1967, he appeared in the first part of "The Judgment", the two-episode conclusion of The Fugitive, starring David Janssen. Constantine played a long-suffering anti-organized-crime agent in Walt Disney's caper film The North Avenue Irregulars (1979), where he appeared alongside Edward Herrmann and Cloris Leachman. He also played an organized crime mobster who worked for Frank Nitti in the television version of The Untouchables. In 1988, he played the estranged father of one of the main characters in Friday the 13th: the Series.
He played Santa Claus in Prancer (1989). In 1993, Constantine appeared in the independent drama Question of Faith, starring Anne Archer and Sam Neill. He played Tadzu Lempke in Stephen King's Thinner (1996). In 2002, he enjoyed an unexpected comeback as the Windex-toting Gus Portokalos in the hit movie My Big Fat Greek Wedding, a role he reprised on the short-lived television series My Big Fat Greek Life, and a sequel film with the original cast, My Big Fat Greek Wedding 2, which was released on March 25, 2016, which ended up being his final major acting role of any kind.7
On October 5, 1953, Constantine married actress Julianna McCarthy, whom he met while in the cast of Inherit the Wind. They had two children, Thea Eileen and Brendan Neil. The marriage ended in divorce in 1969, the same year that Constantine began his role on Room 222. He married Kathleen Christopher in 1974 and they divorced in 1980.8
Constantine died at his home in Reading, Pennsylvania, on August 31, 2021, at age 94, from natural causes.910 My Big Fat Greek Wedding 3, which was released two years after his death, was dedicated to his memory alongside Constantine Vardalos (Nia Vardalos' father) and Bruce Gray (who plays Ian Miller's father, Rodney, in the films).11
Kehr, Dave (April 19, 2002). "FILM IN REVIEW; 'My Big Fat Greek Wedding'". The New York Times. Retrieved February 22, 2019. https://movies.nytimes.com/movie/review?res=9D03E7D9153FF93AA25757C0A9649C8B63 ↩
Hatza, George (December 20, 2014). "George Hatza: Michael Constantine prepares for 'Greek' sequel". Reading Eagle. Retrieved February 22, 2019. https://www.readingeagle.com/2014/12/21/george-hatza-michael-constantine-prepares-for-greek-sequel/ ↩
Fox, Margalit (September 8, 2021). "Michael Constantine, Dad in 'My Big Fat Greek Wedding,' Dies at 94". The New York Times. Archived from the original on September 11, 2021. Retrieved September 9, 2021. https://www.nytimes.com/2021/09/08/arts/michael-constantine-father-in-my-big-fat-greek-wedding-dies-at-94.html ↩
""Death Valley Days" Paid in Full (TV Episode 1965)". IMDb. Retrieved September 17, 2018. https://www.imdb.com/title/tt0556694/ ↩
""Death Valley Days" The Great Turkey War (TV Episode 1965)". IMDb. Retrieved July 7, 2022. https://www.imdb.com/title/tt0556797/ ↩
"My Big Fat Greek Wedding 2". My Big Fat Greek Wedding Movie. Retrieved July 9, 2016. http://www.mybigfatgreekweddingmovie.com/ ↩
Botch, Don (September 8, 2021). "Reading native and Emmy-winning actor Michael Constantine dies at 94 [Video]". Reading Eagle. Retrieved September 9, 2021. https://www.readingeagle.com/2021/09/08/michael-constantine-reading-native-dies-actor-my-big-fat-greek-wedding/ ↩
Calvario, Liz (September 8, 2021). "Michael Constantine, 'My Big Fat Greek Wedding' Actor, Dead at 94". ET Online. Retrieved October 30, 2021. https://www.etonline.com/michael-constantine-my-big-fat-greek-wedding-actor-dead-at-94-171718 ↩
Weiss, Benjamin (June 27, 2022). "Everything To Know About My Big Fat Greek Wedding 3". Screen Rant. Retrieved April 20, 2023. https://screenrant.com/my-big-fat-greek-wedding-3-announcements-information/ ↩