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- Mason Hammond, Harvard University classicist and Harvard historian
- Truxton Hare, Olympic athlete; elected to College Football Hall of Fame
- Harry G. Haskell, Jr., U.S. representative from Delaware and former president of Abercrombie and Fitch
- Prince Hashim of Jordan
- Ingolv Helland, portrait artist
Read more about this topic: List Of St. Mark's School (Massachusetts) Alumni