Isaiah Roby was born in Dixon, Illinois, to Danielle and Roderick Roby. He has four brothers: Donovan, Ellis, Drew and Kordae. Roby attended and played basketball at Dixon High School, finishing his career as the school's second all-time leading scorer with 1,328 points while setting school records in rebounds (939) and blocked shots (327). Prior to his first season on the varsity team, the school finished with a 1-28 record. That changed quickly when Roby came aboard as Dixon went 76-13 over his final three seasons on the team. As a junior, Roby averaged 12.5 points, 9.8 rebounds, 2.6 steals and 3.7 blocks per game. His strong play was rewarded with second-team all-state Class 3A honors. In his senior season, Roby upped his per-game averages to 19.7 points, 10.5 rebounds, 5.5 assists and 3.9 blocks. He finished eighth in Illinois Mr. Basketball voting and was named second-team all-state by the Chicago Sun-Times. Roby was also a high jumper at Dixon, placing fourth in the high jump in the Illinois Class 2A meet in 2016. During his rookie season with the Dallas Mavericks, he joined other staffers in helping to build a home with Habitat for Humanity. Roby is also active with the Make-A-Wish Foundation. Learn more about Roby by following him on Twitter (@roby_isaiah) and on Instagram (@iroby245). Roby spent three years at Nebraska and did not participate in the NCAA Tournament. Nebraska could have been a bubble team in his sophomore season with 22 wins, but the team still did not qualify for March Madness. Roby's debut with the team in 2016-17 was delayed by a pelvic stress reaction. He still played in 30 games and averaged 3.1 points and 2.9 rebounds. The 6-foot-8 forward played more significant minutes as a sophomore and averaged 8.7 points and 6.3 rebounds in 13 starts. He opened the season with a double-double and a string of three straight double-doubles in February. As a junior, Roby started all 35 games and provided an average of 11.8 points and 6.9 rebounds. He scored a career-high 28 points in an NIT win over Butler. After the season, he declared for the 2019 draft and was selected at No. 45 overall by the Pistons.