He was 89. He passed away of natural causes on Saturday, his family announced through a statement.
Gilroy, who served in the Army from 1943 to 1946 in the European Theatre, also won a Tony Award for "The Subject Was Roses." It premiered on Broadway in May of 1964. He then wrote a screenplay for a 1968 film adaptation starring Jack Albertson and Patricia Neal, which would earn both supporting Oscar nominations and a win for Albertson.
Gilroy also directed movies for television and the big screen, including the 1971 Shirley MacLaine drama "Desperate Characters."
His three sons all currently work in the film industry. Both Tony Gilroy and Dan Gilroy followed directly in their father's footsteps as writer-directors. Tony Gilroy wrote the first three "Bourne" films and co-wrote (with Dan Gilroy) and directed "The Bourne Legacy," which starred Jeremy Renner.
In addition to his sons, he is survived by Ruth, his wife of 62 years, and five grandchildren.