Von Appen was a linebacker and guard at Linfield College in McMinnville, Oregon, where he was a three-time all-conference selection.
After leaving Linfield, von Appen served in the United States Army before resuming his coaching career at the University of Arkansas in 1969.
He resigned during the 1980 preseason in protest of head coach Bart Starr's lenient punishment of defensive end Ezra Johnson, who was caught eating a hot dog on the sidelines during an exhibition game.
Former Stanford head coach Bill Walsh brought Von Appen to the San Francisco 49ers from 1983 to 1988, where his duties included special teams.
When Walsh became Stanford's head coach for the second time in 1992, he brought von Appen back as defensive coordinator.