Washington learned to make daguerreotypes during his freshman year to offset his college expenses. Despite the success of this enterprise, he could not keep pace with his debts. He left Dartmouth in 1844, moving to Hartford, Connecticut, where he taught in a school for black students. Two years later, he opened one of Hartford's first daguerrean galleries. Offering portraits ranging in price from $.50 to $10, Washington attracted a broad clientele, and by the early 1850s was regarded as one of the city's foremost daguerreotypists. But despite his success, Washington worried about the future. Convinced that emancipation alone would not remove the barriers that American society imposed upon its black citizens, he came to regard resettlement in the West African nation of Liberia as the best course of action. Accompanied by his wife and two small children, Washington sailed for Africa in November 1853.
Once in Liberia, Washington opened a daguerrean studio and prospered. He later enlarged the scope of his business by traveling to Sierra Leone, the Gambia, and Senegal, operating temporary studios in each. However, Washington soon became convinced that his future lay in developing Liberia's agricultural resources. He acquired extensive property along the St. Paul River and in time became one of Liberia's principal sugarcane growers. He also took part in the nation's political affairs, serving in both the House of Representatives and the Senate. The last reference to Washington's work as a daguerreotypist dates from 1858.
Washington never regretted his decision to immigrate to Liberia, and when he died in Monrovia on June 7, 1875, his death was mourned as "a severe loss to Western Africa."