Had to perform in his first play "The Haunted Host" (1964) with fellow dramatist William M. Hoffman (author of 'As Is'), because no actors could be found willing to be in a gay-themed play.
Is an unbilled extra in Compass Rose (1967) and The Fluffer (2001).
Got cast in Tricks of the Trade (1968) and Compass Rose (1967) only because director Andy Milligan shot them in the Caffe Cino, where Patrick worked. Patrick had been left on duty to make sure the film company did no harm, and was cast in small roles by default.
Had over 300 productions in Manhattan's Off-Off Broadway theatres in the 1960s. Was called by play publisher Samuel French Inc. "New York's most produced playwright" (1972).
Gave playwright/director/former drag-artist Harvey Fierstein his first male role in "The Haunted Host" in Boston, 1976.
Only playwright to have two weekends designated in his honor by Manhattan Borough Presidents (for his pioneering play about gay teenagers, "Blue Is For Boys" in 1983 and 1986).
His "The Trial of Socrates" was the first gay play presented by the City of New York (1988).
He has the distinction of being the only actor killed on screen by all three of the Planet Hollywood founders: Bruce Willis (in Die Hard 2 (1990)), Sylvester Stallone (in Cop Land (1997)), and most famously by Arnold Schwarzenegger (in Terminator 2: Judgment Day (1991)).
Has played the same character (T-1000) in three different movies. Terminator 2: Judgment Day (1991), Wayne's World (1992) and Last Action Hero (1993).
He reprised his Terminator 2: Judgment Day (1991) character, the T-1000, for the theme park attraction T2-3D, a short film filmed in a new 3-D process that makes the film really appear to jump out at you.
Immediately after being cast in Terminator 2: Judgment Day (1991), he took a martial-arts crash course, then began exhaustive strength, endurance, and weapons-training sessions. "For three months," he says, "all I did was sleep, eat, take vitamins, and train.".
Often receives fan mail and stalker-calls meant for actor Robert Patrick, especially from fans of Terminator 2: Judgment Day (1991).
The appearance of character Dale Gribble from the animated series "King of the Hill" (1997) is based on Patrick.
Received the Robert Chesley Lifetime Award for Gay Playwrighting (1997)
In the mid to late 1980s lived in the same Los Angeles complex with such neighbors such as Jim Carrey (Bruce Almighty (2003)), Ernie Hudson (Ghost Busters (1984)) and Cynthia Ettinger ("Deadwood" (2004), The Silence of the Lambs (1991)).
Has played the fathers of both Elvis Presley and Johnny Cash: Vernon Presley in Elvis (2005) (TV) and Ray Cash in Walk the Line (2005).
Has appeared in two movies with Joaquin Phoenix: Walk the Line (2005) and Ladder 49 (2004).