As a child, Hassam excelled at boxing and swimming at Dorchester High School. A disastrous fire in November 1872 wiped out much of Boston's commercial district, including his father's business. Hassam left high school after two years (at age 17), and by 1880 his family had moved to nearby Hyde Park. Despite his uncle's offer to pay for a Harvard education, Hassam preferred to help support his family by working. His father arranged a job in the accounting department of publisher Little, Brown & Company. During that time, Hassam studied the art of wood engraving and found employment with engraver George Johnson. He quickly proved an adept "draughtsman" and produced designs for commercial engravings such as letterheads and newspapers. Beginning to paint artistically, his preferred medium was watercolor, mostly outdoor studies, and around 1879 began creating his earliest oils.