After graduating high school, Johnston attended McGill University in Montreal, where he graduated with a degree in art history and then returned to Manhattan to study at the Harlem Studio of Art. From there he moved to Grand Central Academy, famed altelier school of classical master Jacob Collins. Modeled after the grand ateliers of Europe, students work daily within the studio of a master painter learning anatomy, plaster cast drawing, grisaille and careful modeling of the human form. At Grand Central Academy from 2008 through 2012, Johnston painted under the tutelage of Jacob Collins, Edward Minoff and Scott Waddell, among others.