Gallent participated in the University Athletic Association of the Philippines for the FEU Tamaraws Men's Basketball team but it ended as the result of a motorcycle accident and lost his right eye in 1988 in Alabang Hills.
Gallent was eventually selected as the Llamados head coach with Gregorio's departure to the Meralco Bolts at the end of 2009–10 PBA season.
B-Meg Derby Ace Llamados started the 2010–11 PBA season without three starters Kerby Raymundo, Marc Pingris and Rafi Reavis because of injuries.
Under Gallent's watch, The Llamados recovered and streaked to consecutive wins in the elimination round with vastly improved plays, showcasing their talent and cohesion even without the injured frontliners.
In the middle of 2023 PBA Commissioner's Cup, Gallent was appointed as San Miguel Beermen's interim coach, while Leo Austria was restricted for medical reasons.