A former illustrator and designer in the field of advertising in New York City, Trondsen started out as a still-life painter and eventually moved to painting landscapes full-time. He draws on the aesthetic of the Hudson River School and the Tonalists but his painting style is rooted in contemporary techniques. This melding of traditions produces work of ethereal mood and lovely repose that, thankfully, do not feel dated or stylistically stale.
Primarily a studio painter, he tries to idealize in his paintings his impressions of the countryside that he grew up in - to return to his past conscious and subconscious experiences of the natural world as inspiration for the new work. George Inness's paintings of spiritual and atmospheric scenes are a primary influence on Trondsen's work. So, too, is the idea that a well-composed and affectively strong work of art is a more important end than painting just a "true-to-life", literal version of the landscape. Trondsen is impressed by Inness's "attention to lack of detail".