Helmick said he expected a close race with Leonhardt.
"It was an aggressive campaign against us," he said.
Beginning in the primary, Helmick's opponents repeatedly insisted he was not fit for agriculture commissioner because he does not raise crops or livestock.
State law says the agriculture commissioner should be a "practical farmer" and have made agriculture his or her "chief business" for 10 years before being elected.
Helmick defended his business, saying his bottled water is an "agricultural product." He also stressed his experience as a businessman and state senator would be more important to the commissioner's office than farming experience.
He also had the court system on his side.
In March, Kanawha Circuit Judge Duke Bloom ruled against an attempt to remove Helmick's name from the ballot. Bloom said the law's requirements are unconstitutional and unenforceable.
Voters cast almost 60,000 ballots for Helmick in May's primary election, giving him 33 percent of the vote to beat fellow Democrats Joe Messineo, Steve Miller, Sally Shepherd and Bob Tab.
The victory did not quell questions about Helmick's candidacy, however.
Leonhardt's campaign soon took up the "fake farmer" banner, using the term to describe Helmick in television ads, direct mail flyers, Internet videos and a multitude of tweets.
With his victory, Helmick said he expects lawmakers will now try to strike the farmer requirements from state law.
"It will be forever history," he said.
Douglass joined the state agriculture department in 1957 and was first elected as agriculture commissioner in 1964. He was re-elected six times, stepping aside in 1988 to run for governor. That campaign was not successful -- he lost in the primary to Gov. Gaston Caperton -- but Douglass was re-elected as agriculture commissioner in 1992.Contact writer Zack Harold at 304-3348-7939 or zack.har...@dailymail.com. Follow him www.twitter.com/ZackHarold.