Campbell moved to 15-7 overall with its second shutout win, while Iona dipped to 1-9.
The Camels jumped on the board with three runs in the first, scoring on a pair of wild pitches and a throwing error. Campbell added to its lead in the second frame, with John Reilly scoring on Leonard's sacrifice fly and Danny Pardo stealing home to make it 5-0.
After Reilly led off the home half of the fourth with a hit, Leonard's single through the left side scored the senior to give the game its final score, 6-0.
Campbell starter Andrew Witczak (2-1) earned the win, pitching five scoreless innings with two hits, three strikeouts and a walk. The freshman retired his final 15 batters.
Matt Nadolski fanned two in the ninth with two hits.
Steve Basile (0-1) took the loss for the Gaels, allowing five runs on a hit with one strikeout and five walks in two innings.
Jake Kurz surrendered a run on two hits with a punchout in four innings, and Andrew Pucillo pitched two stanzas, walking a pair.
Pardo and Reilly scored twice each for Campbell in the win, while Nadolski picked up an infield hit and a run.
Joe Torres and Zach Brown both collected two hits apiece to lead Iona.
Campbell heads back on the road this weekend, taking on Big South rival Longwood in Farmville, Va. in a three game series beginning Friday at 6 p.m. The Camels return home on Tuesday, March 25, hosting North Carolina State at 6 p.m. at Jim Perry Stadium.