He attended St. Andrew's Elementary School in Drexel Hill and graduated from West Philadelphia Catholic High School. He then worked in the data-processing department of TV Guide in Radnor, where he met his future wife, Maryanne Conley. They married in 1960 and raised six children in Drexel Hill.
In the late 1970s, Mr. Knapp returned to St. Andrew's and coached football there until the late 1990s. He received the John Stack Coaching Award and was a member of the St. Andrew's Athletics Hall of Fame.
For 30 years, he also coached Little League and Babe Ruth baseball teams in Delaware County, and coached a grandson's team before retiring in 2002.
He was there for any activity involving his children or grandchildren, and taught them how to ride a bike, use in-line skates, drive a car, and tackle, his son Jim said.
Though Mr. Knapp was a proficient golfer, his son said, the game for him was not about the score but about spending time on the course with friends.
He could be stubborn and never met an argument he couldn't win, deploying intelligent, well-informed opinions, his son said.
In addition to his wife and son, Mr. Knapp is survived by daughters Mary Kay McClatchy and Debbie Dunn; sons Bob, Dan, and Kevin; three brothers; two sisters; 18 grandchildren; and one great-granddaughter.
Friends may call from 5 to 9 p.m. Tuesday, Oct. 16, at Stretch Funeral Home, 236 E. Eagle Rd., Havertown, and from 10 a.m., followed by a Funeral Mass at 11, Wednesday, Oct. 17, at St. Andrew Roman Catholic Church, 3500 School Lane, Drexel Hill.
Donations may be made to Juvenile Diabetes Foundation, 225 City Ave., Suite 104, Bala Cynwyd, Pa. 19004.
Contact Sally A. Downey at 215-854-2913 or firstname.lastname@example.org.