Joseph M. Murphy, 61, chairman of the physical education department at Northwestern High School in Hyattsville, died Thursday at Doctor's Hospital of Prince George's County after a stroke.

In his 26 years with Northwestern he had coached in all sports.

Born-in Wilmington, Del., Mr. Murphy was a graduate of the University of Maryland, where he starred in football and track. During World War II, he served as an Army first sergeant in the Pacific and European theaters.

After the war, Mr. Murphy joined the Prince George's County school system, serving for six years as athletic director and coach at Mount Rainier High School before transferring to Northwestern.

He was a member of American Legion Post 136 in Greenbelt.

He is survived by his wife, Mary M., and a son, George, both of the home in Lanham: two other sons, Michael J., of Greenbelt, and Patrick T., of Glenn Dale; a daughter, Ann E. McNally, of Glenn Dale; a stepson, William Brasted, of Riverdale; a sister, Vera Doherty, of Wilmington; two brothers, Thomas, of Carneys Point, N.J., and Millard, of Pennsylvania, and six grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Fund.