Clark is a first-generation farmer from McGregor. He and his wife Kristine operate Wikner Family Farms LLC with their sons, Neal and Ben. They raise 60,000 hogs annually in a segregated early weaning operation, as well as farm 650 acres of corn and soybeans. Clark served on the Clayton County Pork Producers board for six years, including two terms as president. He was on a committee that raised money and constructed a new swine building and show ring for the Clayton County Fair. He is currently a member of IPPA's Iowa Pork Tent committee, and a past member of IPPA’s swine health and well-being committee.
Clark was named a Master Pork Producer by IPPA in 1984.