leading British-American actor and theatrical manager.

Born into a theatrical family, Wallack appeared at an early age at Astley's amphitheatre with his parents and siblings. After an unexceptional early career he developed into a distinguished actor and by 1824 was leading player at the Chatham Garden Theatre, and later at the Covent Garden. In 1829 he played Julius Caesar to his brother James (Wallack, James William)'s Antony.

Wallack (Wallack, James William) had made his American debut in Baltimore in 1819 and first appeared in New York in 1821, and he thereafter traveled frequently between London and New York. In 1837 he joined his brother in taking over the National Theatre in New York, he as stage manager and James as general manager. The partnership lasted for two years until the theatre burned, and Henry returned to acting, performing until 1858. Wallack's three children—Fanny, Julia, and James William Wallack II (Wallack, James William, II)—also were gifted actors.