Cavanaugh is a fourth generation Nebraskan. John Cavanaugh was elected to the Nebraska Unicameral Legislature in 1972 and was elected to the United States House of Representatives from the Second District in Nebraska in 1976 where he served until 1980. Among his civic activities, Cavanaugh served for 20 years as a trustee of the Platte River Whooping Crane Habitat Trust and received a Presidential appointment as chairman of the Czech and Slovak American Enterprise Fund. John Cavanaugh currently serves on the Board of Directors of Citizens Network for Foreign Affairs. Cavanaugh and his wife Kathleen have eight children.