He was born in Plainfield, N.J., came to Princeton from Kent School, served in the Navy, and graduated in 1947 as an aeronautical engineering major. After earning an M.B.A. from Penn’s Wharton School, Marsom spent most of his busy and successful business career as a partner in Adams, Harkness & Hill in Boston.
He then spent his 70s studying photography, filmmaking, sculpture, and painting, inspired perhaps by a stay in Paris after Wharton. He received a bachelor of fine arts degree from Massachusetts College of Art and Design in 2002.
Marsom and his first wife, Bettina, raised three children in Cohasset, Mass. He married Laura Bernard in 2000 on Boston’s Charles River, celebrating with a brass band, lemonade, and watercress sandwiches.
He is survived by Laura; a son, Marsom II; two daughters, Laura Pratt and Drusilla Pratt-Otto; a stepdaughter, Daphne Bernard; and four grandchildren.