James Fahnhorst (born November 8, 1958) is a former National Football League linebacker from 1984 through 1990. During that span he was a member of three Super Bowl Champions and started in Super Bowl XXIII: Super Bowl XIX, Super Bowl XXIII and Super Bowl XXIV for the San Francisco 49ers. He played college football at the University of Minnesota where he was First Team All-Big Ten at Linebacker AP/UPI in 1981. He is the younger brother of former 49ers' tackle Keith Fahnhorst.