Charles J. Hamm was born in Brooklyn in 1937, the son of Lisbeth Higgins Hamm and Frank Hamm. His childhood home was on Pierrepont Street in the Brooklyn Heights neighborhood. He attended Brooklyn Friends School, Packer Collegiate Institute, Berkeley Carroll School, and Polytechnic Preparatory School; all in the borough. He went on to Phillips Exeter Academy and after serving in the Army, he attended Harvard, then received a graduate degree in business at New York University. During his advertising career, Hamm worked for McCann Erickson Worldwide as Executive Vice President and Vice Chairman of their United States division. In 1975, he became Trustee of Independence Community Bank Corporation, then President in 1985. For much of his time with the bank, he and his wife, Irene, lived in Brooklyn Heights. After retiring in the early 2000s, they resided in Mystic, Connecticut and kept an apartment in the Bronxville neighborhood of Manhattan. His board memberships have included Pratt Institute, Brooklyn Botanic Garden, and Brooklyn Academy of Music.