Born in Baltimore and raised on Edmondson Avenue, he attended St. Edward Roman Catholic School and was a 1937 graduate of Calvert Hall College High School, where he played football. He earned a mechanical engineering degree at the University of Notre Dame.
During World War II, he served in the Navy aboard the USS Dufilho in the Pacific. His ship helped rescue crew members of the USS Indianapolis, a cruiser that was the last major naval vessel lost to a torpedo in World War II. He left military service as a lieutenant.
Mr. Hartman was a mechanical engineer and owned his own consulting firm, William W. Hartman Engineers, at Charles and 25th streets. During his career, he worked on projects that included Calvert Hall College in Towson, nursing homes for the Little Sisters of the Poor and Villa Julie College, now Stevenson University.
He was a member of the Baltimore Chapter of the Notre Dame Club and a volunteer at St. Elizabeth School for Special Education, Meals on Wheels of Central Maryland and St. Joseph Medical Center. He also helped prepare tax returns for senior citizens.
He was an Oak Crest Village resident for the past 15 years.
Survivors include his wife of 69 years, the former Anna Lee Keeley; a son, Duke Hartman of Denver; three daughters, Nancy Carter of Grand Junction, Colo., Sally Sexton of Baltimore and Kathy Holt of Hanover, Pa.; 10 grandchildren; and 17 great-grandchildren.
A funeral Mass was celebrated Dec. 30 at the Oak Crest Chapel.