He stepped into acting with stage. In 1952, he got acquainted with ‘Off-Broadway’ productions and the touring repertory-theatre company ‘American Savoyards’ that paved his way for the national tours of Gilbert and Sullivan's ‘The Mikado and Patience.’
He later took his first professional training in acting at the ‘HB Studio’ in Manhattan, under the tutelage of famous American actor, director, and acting teacher Walt Witcover. Eventually, he developed a passion for drama and musical theater.
The acclaimed American drama series ‘East Side/West Side,’ where he featured as ‘Charley’ in the episode ‘The Street,’ in 1964, marked his TV debut. He was recommended for the role by George C. Scott.
In 1965, he made his ‘Broadway’ debut with the Peter Coe-directed English musical ‘Oliver!,’ which ran at the ‘Martin Beck Theatre’ for 64 performances. He performed as ‘Mr. Sowerberry’ with Victor Stiles playing ‘Oliver.’
The years that followed, saw him appearing in many other ‘Broadway,’ ‘Off Broadway’ and regional theater productions. The venues included the ‘New York Shakespeare Festival,’ the ‘Long Wharf Theatre’ and the ‘Yale Repertory Theatre’ among others. He would often play the rhythm guitar and sing in restaurants and taverns to ease his pocket crunch.
He had a stint at the ‘Drug Commission of New York State’ as a recreational worker in a rehabilitation center and gave guitar lessons to women serving their terms for committing drug-related crimes. His humanitarian efforts earned him the ‘Ellis Island Medal of Honor’ in 2010.
Soon, he earned one of the most memorable roles of his career, ‘Johnny Ola,’ in the American crime film ‘The Godfather Part II,’ produced and directed by Francis Ford Coppola. The Oscar-winning film, which starred Al Pacino and Robert De Niro and released on December 1974, not only became a huge commercial success but also emerged as one of the greatest films in the history of American cinema, particularly in the gangster genre.
‘The Godfather Part II’ gave him initial recognition and made his way for other notable roles in films and TV, spanning across various genres. This helped him display his acting mettle and versatility with great élan.
He shared screen space with friend Al Pacino in two more commercially hit films, namely, ‘Dog Day Afternoon’ (1975) and ‘...And Justice For All’ (1979). The directorial debut of Al Pacino, the 1996 documentary film ‘Looking for Richard,’ also featured Dominic. He also performed in several plays with Al Pacino.
In 1981, he played ‘Alexei Vartova’ in 40 episodes of the popular American soap opera ‘Ryan's Hope,’ which originally aired on ‘ABC’ for 13 years, from July 1975.
His fame reached new heights after he portrayed the character of ‘Corrado John Soprano Jr.,’ a smart, old-fashioned, difficult-to-handle senior Mafia member of the ‘DiMeo’ crime family, in the American crime-drama TV series ‘The Sopranos.’
His brilliant characterization in ‘The Sopranos’ in all its six seasons that aired on ‘HBO’ from January 10, 1999, to June 10, 2007, earned him a nomination for the ‘Primetime Emmy Award for Outstanding Supporting Actor in a Drama Series’ in both 2000 and 2001. He also performed the 1911 Neapolitan song ‘Core 'ngrato,’ composed by Salvatore Cardillo, in the Season 3 finale of ‘The Sopranos,’ titled ‘Army of One.’
Apart from acting, he has also carved a niche for himself as a proficient tenor and musician. In 2000, he released the CD ‘Hits,’ which included various American and Italian numbers sung by him. His second CD, encompassing 16 classic Neapolitan songs, titled ‘Ungrateful Heart,’ was released by ‘AOL Music’ in 2003.
He appeared in several other notable American films and TV productions, illustrating his wide range of acting. These included films such as the 1976 political thriller ‘All the President's Men,’ the 1990 crime film ‘Q&A,’ and the 2011 family comedy ‘Mr. Popper's Penguins’; TV series such as ‘Damages’ (2010) and ‘Boardwalk Empire’ (2011–2013); and TV movies ‘Gotti’ (1996) and ‘Crimes of Fashion’ (2004).
His forthcoming film ‘Umberto D.,’ slated to release in 2019, will feature him in the titular role.