Cain founded a Shakespeare company in Boston.
He wrote the television series "Nothing Sacred" a controversial depiction of life in a modern Catholic parish, which aired in 1997-98 on ABC.
His play Equivocation was produced at City Center in New York City in March 2010. It was also produced at Oregon Shakespeare Festival in Ashland, Oregon, and at Seattle's REP,[clarification needed] and as part of the 2014 season at Will Geer's Theatricum Botanicum in Topanga, California, with Ted Barton, Alan Blumenfeld, Dane Oliver, Franc Ross, Taylor Jackson Ross, and Paul Turbiak in Mike Peebler's production hailed by the Los Angeles Times as a Critics' Choice.
His play How to Write a New Book for the Bible was produced at Seattle's REP, January 13 to February 5, 2012, and afterwards, at various venues around the country. The play is based on Cain's own family.
- John Coleman (2010-11-09). "9 Circles". America Magazine. Archived from the original on 2014-03-07. Retrieved 2014-03-06.
Jesuit playwright Bill Cain S.J., has penned a new and searingly powerful play. Just a year after his earlier successful play about the gun powder plot, Equivocation (see my review), Cain portrays in his new play, 9 Circles, a character, Daniel Reeves, as a disturbed 19-year-old snarled in the web of war. Cain's drama mirrors, through a fictional adaptation, the 2006 Iraq slayings and, subsequent, gang rape of a 14 year old girl by United States troops. Like the real life Pvt. Steven Dale Green who, partially, serves as the prototype for Cain's Reeves and now awaits life prison without parole for his war crime, the fictional Reeves displays an 'anti-social personality disorder'.
- Chris Jones (2013-09-18). "Looking for trouble in a war zone in '9 Circles'". Chicago Tribune. Archived from the original on 2014-03-06. Retrieved 2014-03-06.
Or maybe that should be what a man can do to a war. "9 Circles" revolves around a central character, Private Daniel Reeves (Andrew Goetten), who already has been in plenty of trouble before he walks into the office of a recruiting officer looking for soldiers to go to Iraq. Cain's point, surely, is that Daniel, who goes on to commit horrible crimes that appall even the judicial system set up to process and try him, is precisely the wrong kind of man to be allowed to carry military-grade weaponry. The stresses of war, the play argues, could send anyone over the edge. When starting with a guy wound tight enough to burst his own blood-vessels, the smart leader would anticipate trouble.
- Charles Isherwood (2010-03-03). "If He Can, Above all, To His Own Self Be True". New York Times. Archived from the original on 2014-03-07. Retrieved 2014-03-07.