Harper's new crew trailed the Toronto Blue Jays 1-0 entering the bottom of the first inning at Spectrum Field, following a solo homer from Randal Grichuk.
The right-handed pitcher toss his first offering toward the middle of the strike zone and Harper didn't miss it.
The superstar slugger pelted the pitch to right field, clearing several fences at the spring training facility and giving the Phillies a 2-1 advantage.
Philadelphia added three more runs in the bottom of the second, courtesy of a Vince Velasquez RBI ground out and a two-run blast from McCutchen. Lourdes Gurriel Jr. cut the Phillies' lead to two runs with a two-run homer in the top of the third frame.
Harper is now hitting .167 this spring, after entering the game 1-for-10 in six games at the plate. He was 1-for-2 with two RBIs, a run scored and a strikeout through four innings on Thursday's game.
The Phillies face the New York Yankees in another spring training matchup at 6:35 p.m. EDT Friday at George M. Steinbrenner Field in Tampa, Fla.