Marolt defeated challenger Greg Younger by 98 votes, with the certified vote totals showing Marolt with 5,334 votes to Younger's 5,236 votes, which includes absentee and affidavit ballots.
Younger gave notice of his retirement as tax collector earlier this year after serving six terms to run for the chancery office.
Marolt and Younger were the only two candidates, so the office was decided in the Democratic primary.
"I just want to thank the people for coming out during the hot weather, 104-degree temperatures, to vote for me," Marolt said Wednesday. "I want to thank my family for their help in the campaign, my former students and their families and grandparents, who helped me get elected as they did in 2007."
Marolt is completing his first term. He was elected after retiring from teaching in Alcorn County schools, most recently at the Alcorn County Career and Technology Center.