In the late 1860s, after an extensive trip to Norway, Herzog settled permanently near Philadelphia in the United States. Thereafter, he traveled throughout the U.S. and Mexico. He painted his way across the western states, arriving in California in 1873. His works from this trip included a series of Yosemite Valley paintings. In 1876, he received an award at the Philadelphia Centennial Exhibition for his painting of Sentinel Rock in Yosemite. Herzog also made extensive trips to Maine and Florida to paint.
Because he was a prudent investor, Herzog did not have to depend on the sale of his artwork to maintain a comfortable lifestyle. Following his death, his family retained a large group of his paintings, most of which were released to the art market in the 1970s. A number of prominent American and European museums now include Herzogs work as part of their collections.