Inverness-born Knox, who previously played on the tour in 2012, finished 20th on the feeder circuit's rankings, with the top 50 players earning cards for next season's PGA Tour.
His one-under-par final round of 69 in the Web.com's shoot-out at TPC Sawgrass was good enough for him to finish in a tie for sixth place, which shot him up the rankings and comfortably back onto the PGA Tour.
This was the first year of the all-new Web.com Tour Finals, which had a similar structure to the main PGA Tour, with a regular season followed by a season-ending series of tournaments.
"It was a rollercoaster of a day. I'm just so proud of what he has accomplished."
The series consisted of four tournaments, contested by the top 75 on the Web.com Tour regular-season money list, plus the players finishing between 126 and 200 on the FedEx Cup points list.
A total of 50 PGA Tour cards for the following season were awarded at the end of the Finals - 25 to the top regular-season money winners on the Web.com Tour, with the remaining 25 determined by total money earned during the finals.
Knox, who turned pro in 2007 after completing a golf scholarship at Jacksonville University, made 12 cuts from 15 starts on the Web.com Tour this season, as well as eight of 11 cuts on main the PGA Tour.
Speaking to the Golf Channel afterwards, Knox's father Mike said: "It was a rollercoaster of a day. I'm just so proud of what he has accomplished."