Grell’s large theatre mural designs combined are unquestionably his Magnum Opus.  Commissioned primarily throughout the 1920’s and 1930’s where many are over one hundred feet in length.

Grell imagineered countless scenes.  This is to say something entirely unique in setting, location, time and character.  The many landscape scenes existed only in Grell’s imagination until he put oil on brush and applied it to canvas.  Many are based on folklore or Greek mythology and history, but its the select many pictures that absolutely only resided in his imagination that stand out.

In 1917 and 1918, Grell taught art classes at the Chicago Academy of Fine Arts where, according to his sister Helen, Walt Disney was one of his students.

At a time when modernism was taking over the world art scene and turning its back against the old-school traditional styles, Grell appeared to ‘buck the system’ by continuing to earn countless commissions where he chose to incorporated many of those traditional figural scenes.  He continued to rebel against the trends until his death in 1960.