Lown shot a second-round 2-under-par 70 on Tuesday in a U.S. Amateur sectional qualifier at the Brickyard at Riverside in Macon, Ga..
Lown, who was tied for 13th place after a first-round 72, won a three-man sudden-death playoff for the fifth and final spot.
Lown parred the first playoff hole to beat incoming Clemson freshman Cody Proveaux, of Leesville, S.C., and Corey Carlson, of Green Cove Springs, Fla., for the final spot.
The U.S. Amateur starts Aug. 13 at Cherry Hills Country Club in cherry Hills Village, Colo.
Of the other area players to make the 18-hole cut, Sam Odi shot 75-74–149, Taylor Gove had 76-76–153, C.J. Liner and Evan Usry both shot 74-81–155 and Jesse Key shot 76-83–159. Patrick Newcomb, of Benton, Ky., was the medalist at 68-70–138.
Robert Mize, one of Larry Mize’s son, finished fourth with rounds of 72-69–141.