Tatianna Jackson led Lovett with 20 points, while Sydney Umeri scored 13 and Johnson 12. Kaela Davis led Buford with 14 before fouling out.
The Lions (28-5) had never advanced past the quarterfinals prior to this season.
Johnson finished with eight points in the fourth quarter, and each of her baskets put more distance between her team and the Wolves.
Buford (25-8) trailed by as many as 11 in the second half after three third-quarter 3-pointers by Umeri. The Wolves never got closer than four in the fourth quarter.
Buford, which won its previous three title games by an average of 20 points, didn’t score a point for the first seven minutes of the game.
WHITEFIELD ACADEMY 73, ATHENS CHRISTIAN 50
Kenneth Gaines scored 26 points to lead Whitefield Academy over Athens Christian in the boys championship game.
Eric Lockett added 18 points for the Wolfpack, who won their third state championship.
Will Jackson led Athens Christian (30-3) with 20 points, while Zach Lillie added 18.
The Wolfpack (29-3) pulled away from the Eagles after leading by five at the end of the first quarter. The Whitefield defense held Jackson to only five points in the second half after the freshman scored 15 in the first half.
Athens Christian never got closer than 20 points in the second half.
Whitefield finished the season with 21 victories in a row, all but four coming by double digits. All three of the Wolfpack's state championships have come since 2003.
WESLEYAN GIRLS 68, SW ATLANTA CHRISTIAN 44
Katie Frerking scored 20 points to lead Wesleyan over Southwest Atlanta Christian in the girls title game.
The Wolves (29-4) became the third girls team in state history to win five consecutive state championships. Only Hart County, which won six Class AAA titles in a row from 1989-94, has won more in a row.
Wesleyan has won state championships in nine of the past 11 years.
Holli Wilkins added 19 points for Wesleyan.