Mr. Hammer was also a force in teaching, instructing students in acting, improvisation, comedy technique and dramatic literature at Catholic University from 1966 to 1989.

His Arena credits included Sheridan Whiteside in The Man Who Came to Dinner, Captain Shotover in Shaw's Heartbreak House, Pozzo in Beckett's Waiting for Godot and prosecutor Tom Norman in Emily Mann's Execution of Justice..

Mr. Hammer was twice nominated for the D.C.'s major theatre prize, the Helen Hayes Award, for Joshua/Cathy in Cloud Nine and Old Ekdal in Lucien Pintilie's staging of The Wild Duck.

He also occasionally trod the boards of New York, twice on Broadway: in Much Ado About Nothing in 1972; and as Creon in Diana Rigg's 1994 production of Medea. He acted in several Shakespeare productions in Central Park. Most recently, he appeared as Father Lux in the 2003 LAByrinth Theater Company Off-Broadway staging of Our Lady of 121st Street. Mr. Hammer was born April 28, 1937, in San Jose and graduated from Stanford University in 1959. He received a master's degree in fine arts in theater from Catholic University in 1962 and was enrolled for a year in the doctoral program in theatre at Stanford.

Diabetes and a car accident led to the amputation of both his legs in 2001. He continued to act, however. His marriages to Edna Joyce Clark Hammer and Carolyn Swift Jones Hammer ended in divorce. He is survived by two children from his first marriage, David Hammer of the District and Kate Hammer of London; and a granddaughter.