He drew sketches of his view from Powell's Plateau, and then completed the artwork in his studio, with the help of Powell's photographs. The painting is vast, measuring an impressive 7ft by 12ft, which in itself reflects the grand scale of the canyon. Moran has captured the scene as a storm passes over the canyon, with the skies to the left still dark and ominous, and the sky on the right looking clearer and brighter. Straight in front of the viewer is a massive drop, and this shows how fearsome and dangerous the canyon was back then. Congress purchased the painting, and it was displayed in the Senate Lobby, alongside Moran's other artwork Yellowstone Canyon, which he completed in 1872. Both of these artworks can now be viewed at the Smithsonian American Art Museum in Washington.

His brother, Edward Moran, was also a painter, and specialised in maritime artwork. The brothers shared a studio together. Thomas Moran's artistic career began with an apprenticeship at a wood-engraving firm, when he was a teenager. He found the work dull, and started painting watercolours in his spare time, before studying under James Hamilton. He became fascinated with the work of Turner, and even visited England so he could see his artworks in the flesh. The Chasm of the Colorado was typical of Moran's masterpieces, so much so that he was known as one of the painters from the Rocky Mountain School. The other artists in this group were Thomas Hill, William Keith, and Albert Bierstadt. They were known as this due to their numerous artworks of Western landscapes. Moran still painted into his later years, and became a member of the National Academy of Design in 1884.

His status was solidified even further when Mount Moran, in the Grand Teton National Park in Wyoming, was named after him, alongside the viewpoint, Moran Point, at the Grand Canyon. His house in East Hampton, New York was also designated as a National Historic Landmark. One of his landscape artworks, called The Three Tetons, is on display in the Oval Office of the White House.

The Chasm of the Colorado in Detail Thomas Moran