Born in Philadelphia, Pennsylvania of French and Scotch parentage, Edwin Lamasure, Jr. became a noted self-taught landscape artist, as well as painter of marine scenes, primarily using watercolors and working from a studio in Washington, D.C. There, he was active in art clubs and exhibited regularly at the Veerhoff Gallery and with the Washington Watercolor Society. Much of his subject matter was in Virginia and Maryland, and he spent a significant amount of time in the Blue Ridge Mountains and the Chesapeake Bay region. He also painted historical buildings such as The Washington Monument, Mount Vernon and Monticello.

He was commissioned by the Osborne Company to paint twelve scenes of the construction of the Panama Canal, most of them used on calendars, but the circumstances of the commission are unknown. He arrived in Washington, D.C. as a child of eleven in 1877, when his father went to work for the Bureau of Engraving and Printing. In 1883, Edwin Lamasure Jr. went to work for the Bureau as an apprentice engraver, but several years later returned to Philadelphia for several years to work for engravers Bailey, Banks & Biddle, a jewelry store.

The length of his stay is unknown, but in 1895, he is again listed in the Washington D.C. directory. In May, 1896, he married Bertha Prescott Stearns of Wellston, Ohio, and they bought a home in Round Hill, Virginia where he found many of his landscape subjects. They had three children, and in 1902, moved back to Washington, using the Round Hill home for their summer retreat.