Sloan painted landscapes, still lifes, and figurative subjects. A resident of West Philadelphia, he often depicted his own neighborhood and other locations across Philadelphia. Sloan instructed and influenced generations of students at the Pennsylvania Academy of the Fine Arts (PAFA), where he taught from 1962 until his retirement in 1997. His students included Moe Brooker, Richard J. Watson, James Brantley, Edward Ellis Hughes, and Barkley L. Hendricks. At the time of Sloan’s death, Hendricks remarked, “Lou Sloan was one of my major influences at PAFA and when I heard he had died, I had a sinking feeling in my heart. I loved the man. He was a friend and a fantastic instructor. I’ve always said that Lou was one of the best painters on the planet.”
Sloan received early art training at the Samuel S. Fleisher Art Memorial. He was encouraged to study at PAFA by instructor Julius Bloch and alumnus Jack Bookbinder, the head of art programs for the Philadelphia public schools. He attended PAFA from 1953 to 1957 and, in addition to his tenure there, he worked in the conservation department at the Philadelphia Museum of Art from 1961 to 1980. Sloan is represented in the collections of PAFA, the Philadelphia Museum of Art, and the African American Museum in Philadelphia.