Mac was born March 25, 1930, in Chicago to Fred and Louise Voltz Bollman. A graduate of Chippewa Falls High School in Wisconsin, he majored in music at Princeton, where he was a member of Key and Seal, the band, and the Chapel Choir. He left Princeton in 1950 to join the Navy and was a night-fighter pilot until his separation in 1955.
He married Lucile Roesler in 1957. Mac earned a bachelor’s degree in economics from NYU. He was with Merrill Lynch for three years, after which he joined an international group composed of companies under the Amsinck Sonne Corp. umbrella. He worked first in Brazil for two years with Gillespie Inc. and then with the American Trading Co., which brought him to the Far East for three years each in Korea and Japan. After 10 years in the New York office, he was in Indonesia for two years. He then joined Lucy in the travel business.
Mac died June 21, 2013. He is survived by Lucy; their son, McWilliam Jr.; daughter Elly Schmidt; four grandchildren; and his sister, Ann Goldsmith. The funeral was held at Mountain Grove Memorial Church in Huletts Landing, N.Y., on the shore of Lake George in the Adirondack Mountains.