A Distinguished Eagle Scout, Harold Hook volunteered with the Boy Scouts of America for decades. He was a national president of the BSA and a member of the National Executive Board. He has also served as president of the Golden Empire Council and in numerous positions with the Greater St. Louis Area Council, including president and chairman of the board. His dedication to the Boy Scouts was rewarded with the Silver Beaver Award, the Silver Antelope Award and the Silver Buffalo Award.

Harold was the chairman and CEO of American General Corporation, a leading life insurer acquired by AIG. He first entered the top echelon of the insurance industry when he was 31 and was elected president and CEO of National Fidelity, which at the time made him the youngest president of a life insurance firm in the country.