Gideon Jacques Denny was born in Wilmington, Deleware. As a young man, he worked on ships in Chesapeake Bay. At age 19, he headed west in the Gold Rush of 1849. He was a teamster on the San Francisco docks and was a member of the San Francisco Committee of Vigilance.

In 1851, he moved to Milwaukee, Wisconsin where he studied painting with Samuel Marsden Brooks. After six years, Brooks moved to San Francisco with Denny where they shared a studio. By 1868, Denny was 38 years old. He took a voyage to Hawaii where he stayed two months, exploring several islands. He is known to have also visited Canada and South America. He died of malaria in Cambria, California in 1886 at the age of 56. His works reside in the de Young Museum, the Bishop Museum in Honolulu, the Oakland Museum of California and the Berkeley Art Museum.