William Jewell led 29-24 after a back-and-forth first half, but the Kangaroos (1-1) gained the lead for good early in the second when LaVell Boyd hit a 3-pointer and Kyle Steward followed with a layup for a 32-29 edge with 16:51 left in the game.
The game was the Harrison's 20th with five or more assists in a game, with a high of 11. The Kangaroos had 13 assists on 22 field goals.
Matt Lassen, a 6-foot-5 freshman, led the Cardinals with 26 points. Patrick Whelan added 13, but the Cardinals committed 22 turnovers and shot just 15 of 47 (32 percent) from the field. The game saw 60 fouls.