Marks was the son of Charles Pollard Marks and his wife, the former Isabel Caldwell. He graduated from Birmingham University School and earned a degree in physics from the University of the South in Sewanee, Tennessee in 1942. He joined the U.S. Navy for World War II and served in the North Atlantic and Mediterranean as a chief engineer officer.
In 1946 he partnered with Spencer to purchase the Owen-Richards Company, an industrial supplier. They expanded the business regionally and changed the name to Motion Industries in 1972. As president, Marks focused on the company's products and processes while Spencer oversaw the business as chairman. The company was sold to the Genuine Parts Company of Atlanta, Georgia in 1976, but Marks remained with the firm until his retirement in 1983. He and Spencer were also investment partners in the establishment of the engineering and construction firm BE&K in 1972. He also served on the board of directors for the Alabama Federal Savings and Loan Association and chaired the Birmingham Branch of the Federal Reserve Bank of Atlanta.
As chair of the Committee of 100, Marks was one of five representatives of Birmingham's business community that met with President John F. Kennedy and Attorney General Robert Kennedy in the oval office in 1963 to discuss race relations in the city in the face of the Southern Christian Leadership Conference's Birmingham Campaign for Civil Rights.
Marks was active in civic affairs. He chaired the boards of Children's Hospital, the Workshop for the Blind, the Children's Aid Society, the Executive Service Corps of Birmingham, Brooke Hills School, Highlands Day School, and the St Vincent's Foundation. He chaired the Board of Regents at the University of the South. and also chaired the Midtown Redevelopment Authority which consolidated land for construction of the Kirklin Clinic. He co-chaired the United Way and served on the boards of the University of Alabama Health Services Foundation, Southern Research Institute, the UAB Research Foundation, the Birmingham Museum of Art, and Indian Springs School. He was also appointed to the Alabama Study Commission to improve public education.