Hemmerman came through the youth ranks at Hull City as Terry Neill's "Tigers" ended the 1973–74 season in ninth place in the Second Division, and then went on to finish the 1974–75 season in eighth place under the stewardship of John Kaye. He was loaned out to Scunthorpe United in the 1975–76 campaign, and scored one goal in five Fourth Division games at the Old Showground. He was Hull's top-scorer in the 1976–77 season with seven goals. In total, he scored ten goals in 59 league games during his four seasons at Boothferry Park.
