Although Kushner had written the Prior Walter role with him in mind and he had played it at the initial readings at San Francisco's Eureka Theatre (1989), Spinella almost pulled out of the inaugural workshop at The Mark Taper Forum in L.A., fearing he would be unceremoniously dropped when the play moved to New York. His anxieties were not groundless. When Kushner's "A Bright Room Called Day" (1990) was produced at NYC's Public Theatre, director Michael Greif had refused to cast Spinella in spite of his contributions to its development. With the playwright's guarantee that he would be a part of "Angels" wherever it went, Spinella persevered, earning two Tony Awards and two Drama Desk Awards for his efforts.
He received an OBIE Award for his work as a buttoned-up accountant, half of a long-term gay couple, in Terrence McNally's "Love! Valour! Compassion!", a role he reprised in Joe Mantello's 1997 feature adaptation. Spinella has periodically returned to the NY stage, appearing in "Troilus and Cressida" in Central Park and portrayed Thomas, the longtime lover of an AIDS patient who is contemplating suicide, in David Rabe's "A Question of Mercy" (1997).
Spinella's film debut came as the villainous Lindenmayer, the creator of a vicious computer-generated serial killer (Russell Crowe) in Brett Leonard's sci-fi thriller "Virtuosity" (1995). He appeared for the first time on TV in a cameo as a man dying from AIDS complications in the Emmy-winning HBO movie "And the Band Played On" (1993). His other feature roles have included a gay real estate agent in "Tarantella" (1995), with Mira Sorvino, and a small role in "The Jackal" (1997), opposite Bruce Willis.