The elder brother of painter Gifford Beal, Reynolds was born in New York City. Beal was a man of independent means, and was thus able to devote his life to his art without having always to appeal to the tastes of his patrons or to contemporary trends.
From 1900 to 1907, he painted almost exclusively at the artist's community in Noank, Connecticut with Henry Ward Ranger. After 1912, Beal focused more on the Hudson Valley, where he painted the colorful and whimsical scenes of the traveling circuses that came through the region.
Beal painted the beaches in Provincetown, Key West, Rockport, Atlantic City and Wellfleet, circus scenes and carnivals. He used a variety of styles including Impressionism and Tonalism. As he got older, his work became more complex and vibrant. In addition to oils, he was admired as a watercolorist, and he and Gifford made Rockport, Massachusetts their home. At one time, he resided in Gloucester, Massachusetts, as well. His studio overlooked Rockport's Inner Harbor, from where he drew and etched many harbor scenes.
Beal traveled widely. In November 1944, Reynolds and Gifford had a large joint exhibition at the Fitchburg Art Center (now Museum) in Fitchburg, MA, which included eighty-three oils, watercolors, and etchings that had been executed all over the world with subjects including Singapore, Trinidad, Samoa, China, Nassau, Egypt, Haiti, Cape Ann, Atlantic City, and Provincetown.