In 2006, he entered the final round with a five-shot advantage. Johnson watched his lead slowly disappear, and he eventually lost on the final hole.
"I think I learned a lot from last year," he said.
Johnson entered the final round of this year's event with a three-shot lead. This time, he produced a better result.
Johnson carded a final-round 1-under-par 71 on Thursday to win by nine shots over Brandon Truesdale at North Augusta Golf and Country Club.
With earlier rounds of 72-69, Johnson finished at 4-under-par 212.
"I just told myself to shoot a round around even par and I'll be OK," he said.
Last year, Johnson's lead dwindled throughout the day, but after making birdie at No. 15, he led by three shots with three holes remaining.
"Toward the end," Johnson said, "I thought I had it."
Wesley Bryan surged with three consecutive birdies. Johnson had an opportunity to salvage a playoff, but he three-putted from 30 feet at No. 18 to lose by one.
This year in the final round, Johnson got off to a fast start. Beginning his last round on the par-5 10th hole, Johnson piped a drive down the middle, knocked an 8-iron to 15 feet and two-putted for birdie.
Johnson, an 18-year-old North Augusta senior, remained steady throughout the day while his three playing partners melted down. Chase Durham, who trailed by three after two rounds, shot 84.
"I don't think I lost my focus," Johnson said. "I really didn't get nervous at all."
Johnson said the experience he's earned in the past year was key. In September, he recorded a team-best five points for South Carolina in the Regions Cup Matches, a Ryder Cup-style match-play event for the top points getters in Georgia and South Carolina.
Two Sundays ago, he gained more experience. Johnson, who has yet to receive any college scholarship offers, played in the final round of the Mercedes-Benz of Augusta Dealer Championship with Augusta State coach Josh Gregory. Johnson, who said he'd like to play collegiate golf close to home, finished in a tie for sixth.
"(Gregory) made me feel comfortable," Johnson said. "He's a nice guy."
Johnson will spend the rest of his summer playing golf. Next weekend, he'll participate in the Goshen Golf Classic on the Regions Cup tour. One day later, he'll travel to Greenville, S.C., for the South Carolina Junior Match Play tournament. One day after that event, he'll head to Thomson for the Camellia Classic.
"I just hope he doesn't get burned out," Johnson's mother, Donna, said.
It might sound like a lot of golf, but he's trying to cram in as much of the sport as he can because of a late start.
Johnson, a former basketball player, started playing golf at 13, joining his buddies.
"It became addictive," he said. "I just wanted to get better every day."
His rapid ascension in the sport culminated last year, when Johnson shot a course-record 11-under-par 61 from the blue tees at Bartram Trail Golf Club. He set the mark a few weeks before his minor setback in the North Augusta Sertoma Junior Invitational.
Reach Chris Gay at (706) 823-3645 or firstname.lastname@example.org.