Esaias Gandy was ranked by 247 Sports as the No. 17 overall recruit in the state of Colorado in the 2017 recruiting class. Gandy earned First Team All-State Class 4A from the Colorado High School Activities Association (CHSAANow.com), ColoradoPreps.com and MaxPreps. The teams were selected by Colorado head coaches from across the state. He ranked No. 5 in the state of Colorado in tackles among all players in all classes, totaling 155 tackles his senior season. Gandy had 76 solo tackles, 79 assisted tackles, 10.0 sacks, 19.0 tackles for loss, one interception, two forced fumbles and averaged 12.9 tackles per game. He added 157 rushing yards and two rushing touchdowns, 243 receiving yards and three TD receptions and accumulated an even 400 all-purpose yards his senior season. Gandy led Denver South to a No. 1 seed in the Colorado Class 4A State Playoffs before losing in the State Quarterfinals. Gandy's Denver South team posted an 11-1 overall record and a 5-0 conference record, winning the Mountain League title. Gandy ended his high school career with 310 career tackles, 143 solo tackles, 27.5 sacks, 20.0 tackles for loss, two interceptions, five fumble recoveries, two forced fumbles and averaged 7.8 tackles per game over his career. He played for head coach Tony Lindsay.
Gandy was also recruited by Arizona, Colorado, Colorado State, Harvard, Kansas and Utah.