Born and raised in Laie, Hawaii, Alohi Gilman played his prep ball at nearby Kahuku High & Intermediate School. Coming out of HS, Gilman committed to play for the United States Naval Academy where he played just one year as a freshman. He recorded 76 tackles and broke up five passes to earn Honorable Mention All-AAC honors.
Following that year in Anapolis, Gilman transferred to Notre Dame but was forced to sit out his sophomore campaign due to NCAA transfer rules. As a junior, Gilman earned a starting role and went on to start 13 games, racking up a career-high 95 tackles, three forced fumbles, two interceptions, and five pass breakups.