Andersen competed between 1907 and 1911 in the Greco-Roman middleweight class in unofficial European and World Championships achieving his best results placing fourth at World Championships in Berlin and Dresden in 1911. He took his only international medal with a bronze at the 1908 Olympics after a bye in the first round and victories over two Dutch opponents. In the semi-final, he lost to the eventual gold medalist Frithiof Mårtensson from Sweden. In the medal round, he profited from the withdrawal of Jóhannes Jósefsson from Iceland due to an injury sustained in the previous round. In 1912, he was eliminated after losing his first two bouts.
Andersen later competed in the lightweight class winning two Danish Championships titles in this class in 1913 and 1914. In 1915, he was runner-up in the middleweight. He continued his career on a regional level until 1920.
Denmark