William Harvey O’Connor III, a retired Black and Decker engineering executive and power tool patent holder, died of heart attack complications Saturday at the University of Maryland Hospital Center. The Forest Hill resident was 75.

Born in Baltimore and raised in Walbrook and Wiltondale, he was the son of William Harvey O’Connor Jr., a Baltimore Gas and Electric Co. engineer, and his wife, Irma Heintz, a homemaker and amateur woodworker.

He was a 1959 graduate of Towson High School, where he ran track and cross country. He obtained a bachelor of science degree in electrical engineering from the Johns Hopkins University, where he was a member of the Reserve Officer Training Corps and a member of the Pershing Rifles drill team. He represented the Panama Canal Zone as he marched in President John F. Kennedy’s inauguration parade.

In 1971 he received a second bachelor’s degree, in industrial management, also from Johns Hopkins.

He met his future wife, Susan Fulkerson, while both were students in an English class at Towson High School.

Mr. O’Connor served in the Army in its Ordinance Corps in Germany. He attained the rank of lieutenant.

After his military service he joined the Black and Decker Corp. and held posts in Towson and at Fayetteville and Raleigh, N.C. He had five patents for power tools and a lawn mower component. He was the safety chair of the Power Tool Institute, a national organization.

He retired from Black and Decker in 2002 as vice president of Engineering Operations of the North American Power Tool Group.

Mr. O’Connor was an Eagle Scout and remained active in Scouting as a Cub Scout leader and assistant Scout master in Fayetteville and Raleigh.

Family members said Mr. O’Connor believed in racial diversity and was a member of the Board of Directors of Advancing Minorities’ Interest in Engineering from 1996 to 2002. They said the organization is composed of industry representatives and engineering school deans of historically black colleges and universities.

He joined the Evangelical Lutheran Church of America’s Maryland Synod’s Racial Justice Ministry Team in 2008 and remained active on the panel.

Mr. O’Connor played the piano by ear and was a weekly ballroom dancer. He enjoyed theater and Baltimore Symphony Orchestra performances. A golfer, he had a hole in one March 23, 2001, at Geneva Farms.

A funeral will be held at 10 a.m. Thursday at Holy Communion Lutheran Church, 621 Old Fallston Road, Fallston, where he had served in several positions, including chair of its building committee and finance committee, and two pastoral call committees. He also served three terms on the Congregational Council.

Survivors include his wife of 53 years, Susan Fulkerson O’Connor, a homemaker and retired part-time Harford Community College English teacher; a daughter, Elizabeth O’Connor Seely of Columbus, Ohio; a son, John William O’Connor of Darien, Conn.; two sisters, Sharon O’Connor of Towson and Dale O’Connor Newhart of Annapolis; a brother, Robert O’Connor of Forest Hill; and five grandchildren.

—Jacques Kelly