Franciosa was born Anthony Papaleo on October 25, 1928, in New York City. The son of a construction worker and seamstress who divorced when he was a year old, he seldom saw his father after this and never man really got to know the other. After graduating high school, during a visit to a YMCA to take a free dance lesson, Franciosa came across an audition for a play. Intrigued, he auditioned and was offered a part.
Franciosa began acting professionally, taking his mother's maiden name as his stage name, and had his breakthrough in Calder Willingham's play "End as a Man" (1955), which opened off-Broadway at the Theatre de Lys on September 15, 1953 and transferred to Broadway on October 14 after 32 performances. It was directed by Jack Garfein and co-starred Ben Gazzara (who won a Theatre World Award and would appear in the movie version), both of whom were associated with the Actors Studio, as was Franciosa. His first wife, Beatrice Bakalyar, was a writer.
In 1955, he first appeared in