Mac graduated from St. Wendlins Catholic High School in Pittsburgh and shortly thereafter entered the US Army. He was a veteran of the Vietnam War and earned the rank of Sergeant First Class before retiring in 1982. He earned numerous award and honors for his service to his country. Mac then earned his certification as an addiction counselor through an affiliate of Penn State. He was a drug and alcohol therapist for more than 20 years and eventually retired from Mazetti & Sullivan Associates in Harrisburg. He also worked part-time in his son's construction company in the York area. Mac was a devoted family man and enjoyed hunting, fishing, golfing, automobile restoration and spending time in Ocean City, Maryland. Mac also had a 35 year friendship with Bill W. and Dr. Bob.

He is survived by his loving and devoted wife of 25 years, Margaret A. "Peg" (Laye) McAllister, two sons; Rick W. (and his wife, Tammie) McAllister of East Berlin and Scott W. (and his wife, Julie) McAllister of Waynesboro, one step-son, Joseph A. (and his wife, Eva) Mills of Marysville, one step-daughter, Marina S. Tolbert (and her companion, Kevin Summers) of Chambersburg, 10 grandchildren, 9 great-grandchildren, many other extended family members and hundreds of other friends in recovery. Mac was preceded in death by one daughter, Michelle McAllister and one step-son, Frank Mills.

Memorial services will be held on Wednesday, March 7, 2012, at 11 a.m. in the New Hope Church of God, 1250 Waggoners Gap Rd., Carlisle, with Rev. Steven R. Osborn officiating. Military honors will be provided by Cumberland County Honor Guard at the church. A time of fellowship will immediately follow the military honors also at the church. Burial will be private. Ewing Brothers Funeral Home, Carlisle, is assisting the family with the arrangements. Flowers are welcome or memorial contributions may be made to the American Heart Association, 1019 Mumma Rd., Lemoyne, PA 17043.