Born in
Philadelphia, he attended the
Pennsylvania Academy of the Fine Arts, where he studied under
Christian Schussele. For several years, he then painted portraits in Philadelphia. Using money earned in Philadelphia, he moved to the coast of
New Jersey, where he began doing marine paintings. In 1881, he married Margaret Selby. They moved to the Hotel Chelsea in
New York City where, with other artists, he kept a studio on the top floor. In 1882, he was awarded the first prize for marine painting at the
St. Louis Exposition. In 1885, he received the first prize at the
water color exhibition of the American Art Association, and in 1886 he won a gold medal at the Prize Fund Exhibition. A son, also named Frank Knox Morton Rehn (18861956), owned a well-known Manhattan art gallery; among the artists he represented was
Edward Hopper. ==Works==