After a federal clerkship, Henry began his legal career with Cleary, Gottlieb, Steen & Hamilton, working in Cleary's New York and Paris offices.  In 1980, he moved to Los Angeles, where he joined Morrison & Foerster, retiring in April of 2025.  In his practice, he advised domestic and international financial institutions on a broad range of matters, including mergers and acquisitions and capital market activities. Henry was named to The Legal 500 inaugural Hall of Fame, a distinction given to those attorneys  listed as a Legal 500 elite leading lawyer for at least six consecutive years. In 2016, he  was awarded Best Lawyers – Los Angeles Lawyer of the Year for Financial Services Regulation Law. Henry  also represented clients in other industries, including branded apparel, consumer goods, and travel services. 

Henry served on the Board of the Starlight Children's Foundation for more than 25 years and coordinated Morrison &  Foerster's pro bono representation of Starlight.  In 2026, Starlight presented him with a Lifetime Achievement Award for his service.  Henry currently serves on the Board of People4Peace, Inc.