After having served in the war, Thrash qualified as a war veteran and enrolled in the Art Institute of Chicago with the support of federal funding. After finishing his education, he traveled intermittently from Georgia to Chicago, Boston, New York, and finally Philadelphia, working odd jobs - experiences that provided him with subject matter to later paint. Settling in Philadelphia by 1925, he took a job working as a janitor. In his free time, he continued his art career and used his talent to create emblems, like for the North Philadelphia Businessmen's Association, and posters in exhibitions and festivals, including the 2nd Annual National Negro Music Festival and the Tra Club of Philadelphia. This gained him local recognition and opened doors for new artistic endeavors. By 1929, Thrash found himself attending nightly classes within these clubs, namely with Earl Horter of the Graphic Sketch Club, now known as the Samuel S. Fleisher Art Memorial.