Districtwide, Henson, a Stone Mountain Democrat, beat McKenzie by 111 votes, according to official results from the Secretary of State's Office.
Henson has served in the Senate for 24 years, first spending eight years in the chamber before leaving in 1998 to run unsuccessfully for labor commissioner. He returned in 2002 and has been the Senate’s minority leader since 2011.
It was Henson’s first primary challenge since returning to office in 2002.
McKenzie, an ordained minister who teaches liturgical dance, was making her second bid to win a legislative seat.
The 47-year-old New York native, who moved to the Atlanta area in 1989 to attend Morris Brown College, ran for the state Senate in a different district in 2004, coming in third in a seven-way race.