Cosgrove is known for his landscapes, still lives, and figure paintings; he had a career that spanned many decades, contributing significantly to the Canadian art scene. Centennial Blue could be reflective of the artist's style during the 1960s, which was characterized by a focus on the interplay of light and shadow, as well as the use of color to evoke emotion and atmosphere. The painting’s title might suggest that it was created in celebration of Canada's centennial year of confederation, which was in 1967, possibly imbuing the work with a sense of national pride or reflection.

The muted yet impactful use of blue hues and the depiction of the serene forest could be suggestive of the Canadian landscape. Cosgrove's technique, which appears both controlled and free, with an impressionistic quality, creates a sense of tranquility and the timeless beauty of nature, themes that were often explored in his work.