Den Herder chose Central College in Pella, Iowa, because of its reputation for education in sciences and its affiliation with the Reformed Church in America.

At 6 feet 6 inches (198 cm) in height, he was the starting center on Central's basketball team for four years and set the school scoring record.

"[6] Seeing that the game had evolved toward more passing-oriented strategies that were not attuned to his run-stopping ability, Den Herder originally decided to retire in 1981, returning to his hometown to work in a cattle feeding operation.

However, Coach Shula asked him to return to the game for one more season after the Dolphins roster had thinned due to injuries.

[3] After retiring from football for the second time, Den Herder returned to Sioux Center, Iowa and became a farmer, now specializing in corn and soybeans.

[3] Due to a harvest, he was unable to join the rest of the 1972 Perfect Season Dolphins at a ceremony in their honor, hosted by President Barack Obama at the White House.