Horn was a gentlemanly, popular and respected racer. One of the best never to win the Indianapolis 500, despite numerous top finishes at the Brickyard. He won the National Championship title in 1946, 1947, and 1948 and became the first three-time winner of the Championship. During those years he placed third twice and fourth in the Indianapolis 500. Thus giving him ten straight finishes in the top four. Crash prone at the very beginning of his career, he survived to become a very smooth driver.
In 1948 he clinched the championship with a third-place finish at the DuQuoin, Illinois track in September. A month later he was killed at the same track he crashed during the second lap. He was named to the National Sprint Car Hall of Fame in 1991 and inducted into the Motorsports Hall of Fame of America in 1993.