After his military service Mack began a long career as an investment banker, business analyst, and acquisitions specialist with several different firms, first in New York City and then in Dallas, Texas, where he was well known and respected in the business community. He also spent several years counseling those afflicted with alcohol addiction and lecturing on the subject. In retirement, he moved with his second wife to Fayetteville, Ark., and after her death relocated to Wichita, Kan., to be close to his children.
Mack died April 2, 2020. He is survived by his three children, Andrew, Richard, and Susan Walker; his brother, Sid Harris ’55; and four grandchildren.