Robert Spears-Jennings attended Broken Arrow High School in Oklahoma, where he played both safety and wide receiver. As a senior, he was the Oklahoma All-District 6A-I Safety of the Year after recording 56 tackles and four interceptions. He also had 36 receptions for 626 yards and eight touchdowns. The four-star recruit committed to the University of Oklahoma as a safety.
As a true freshman in 2022, he collected 15 tackles, including one tackle for a loss for the Sooners. During his sophomore season, Spears-Jennings started two of 12 games and recorded 38 tackles. He had a breakout season in 2024, starting 12 games and registering 63 tackles, five tackles for a loss, 2.5 sacks and four forced fumbles.