Hammerschmidt was a delegate to the Republican National Conventions in 1964, 1968, 1972, 1976, 1980, 1984, and 1988. He was twice the state chairman of the Republican Party of Arkansas, serving from 1964 to 1966 and again from 2002 to 2004. His successor as chairman in 1966, Odell Pollard of Searcy in White County, died three weeks before the death of Hammerschmidt.