At age seven, Moran and his family emigrated from England to Philadelphia, where he was apprenticed briefly to a wood engraver. Although best known as a painter, Moran was also a prolific illustrator. In 1862, after a trip to Lake Superior, which inspired a series of views related to Henry Wadsworth Longfellow's Hiawatha, he and his brother Edward traveled to England. In 1871 Moran accompanied F. V. Hayden's geological survey of Yellowstone as a guest artist, with funding from Scribner's and railroad financier Jay Cooke. During the expedition Moran worked closely with photographer William H. Jackson. In 1872 Moran visited Yosemite and in 1873 joined John Wesley Powell's geological survey of the Grand Canyon and Colorado River. In 1874 he was again with Hayden in Colorado, where he visited the newly discovered Mount of the Holy Cross. Although most of his life was spent in the East, he traveled west frequently, often as a guest artist of the Santa Fe Railway.
William Truettner, ed The West as America: Reinterpreting Images of the Frontier, 1820–1920 (Washington, D.C. and London: Smithsonian Institution Press, 1991)