Im Sung-jae hit the front at the halfway stage of the Corales Puntacana Resort and Club Championship, where Tony Romo missed the cut.
South Korean golfer Im carded a five-under-par 67 to earn a one-stroke lead in Punta Cana in the Dominican Republic on Friday.
Outright fourth at the start of the second round, Im moved top of the leaderboard thanks to eight birdies, which outweighed his double-bogey and bogey.
Jonathan Byrd (67), Aaron Baddeley (67), Paul Dunne (69) and George McNeill (65) are all tied for second at nine under through 36 holes.
Dallas Cowboys great Romo, meanwhile, failed to qualify for the weekend of the PGA Tour event.
Romo – who missed the cut last year – struggled again as the former quarterback posted an 80 to be 15 over after two rounds.