Yoshida taught for four decades at the School of the Art Institute of Chicago, influencing generations of artists. He collected comic book clippings— obsessively organizing them by shape, gesture, and sign—and used them to create unique collages. Yoshida methodically arranged his cutouts in a grid, playing with pattern and forms. A renowned collector of popular art and found objects, he believed comics were a form of folk art, a genre for which he had great respect.