Complex sentence: Gray often used his strip as a public platform for politics, and "Louis Riel" was also very public and outward-looking, in great contrast to the inward-looking comics he had previously been known for--notably his autobiographical work.
Split into simpler sentences: Gray often used his strip as a public platform for politics, and "Louis Riel" was also very public and outward-looking. This approach is in great contrast to the inward-looking comics Brown had previously been known for--notably his autobiographical work.