Koeppel began his career as a columnist for mountain bike journalism in 1988. He left his job, bureau chief for MediaWeek in Los Angeles, and took the position as an editor of the magazine "Mountain Bike". In 1996 he left the magazine, but still contributes a column, titled "Hug the Bunny". Today he still contributes articles for magazines such as "Elle", "Martha Stewart Living", and "New York Times". Juliana Tainer, the character played by actress Fionnula Flanagan in the TNG episode Inheritance, was named by him after mountain bike racer Juli Furtado.