Bradbury began a successful business in Portland, where he ornamented many types of vehicles. As his business became more successful, he began what he is now most famous for: painting.
There is also a rumor that Bradbury was known by Herman Melville, as in Melville's book Moby-Dick Melville makes a reference to "the painter of the saco" meaning the one who painted the Saco River, which is what Gibeon painted most often.
http://www.sacomuseum.org/library/GibeonBradbury.html