He attended public schools in Live Oak and received his Bachelor of Science in Agriculture (Bachelor of Scientific Agriculture) from the University of Florida in 1956. Gunter briefly attended the University of Georgia in 1957 and served in the United States Army from 1957 to 1958.
He was elected as a Democrat to the United States House of Representatives as the member from Florida"s 5th congressional district in the 1972 election, but served only a single term. His voting record in the 93rd Congress was generally moderate. Gunter unsuccessfully sought the Democratic nomination for United States. Senate in 1974, but lost the primary to Richard Bernard Stone.
He was elected Florida State Treasurer and Insurance Commissioner in 1978 and served in this post until 1988.
In 1980, Gunter ran again for United States. Senate, defeating incumbent Senator Stone in the Democratic primary. He then faced the Republican nominee Paula Hawkins, who had been the Republican candidate for lieutenant governor (as the running mate of Jack Eckerd) in the 1978 gubernatorial election.
Gunter"s loss was accompanied by the Republican pickup of 11 other seats, which produced a Republican majority in the Senate for the first time since 1954. Gunter made a final Senate bid in 1988, narrowly losing the Democratic nomination to Buddy MacKay.
In recent years, Gunter has worked at Rogers, Gunter, Vaughn, a Tallahassee-based insurance agency and been active in related trade associations and lobbying for the industry.
While a student at Florida, he was a member of the Sigma Alpha Epsilon Fraternity (Florida Upsilon chapter). He was a member of the Florida State Senate in 1966.