He moved to the United States at age 16 and later played college basketball for the University of Central Florida (UCF).

[9] Fall was listed as 7 ft 6 in (2.29 m) and was purportedly still growing around his senior year, making him the tallest high-school basketball player in the country while he played for Jamie's House Charter and Liberty Christian Prep.

[citation needed] Fall first played for Jamie's House Charter School in Houston, where his team won the state championship.

Rated as a four-star and three-star recruit in the 2015 high-school class,[13][14][15] nearly 40 different schools expressing interest in him,[10] Fall committed to the University of Central Florida in Orlando, who officially signed him on 28 October 2014.

He faced fellow giant Senegalese center Mamadou N'Diaye, who stands at 7 ft 6 in (2.29 m), in the tallest tip-off and match-up in U.S. college basketball history in a game against University of California Irvine.

By his sophomore year, after N'Diaye declared for the 2016 NBA draft, Fall became the tallest player in college basketball.

During his senior season, Fall helped lead the Knights to the 2019 NCAA tournament and secured their first victory in program history with a win over Virginia Commonwealth University.

[26] During the combine, he put up new records at the event, including height (which received comparisons to former NBA player Manute Bol),[27] wingspan, and standing reach.

[32] Fall concluded his 2019 Summer League run participating in all five games with the Celtics and averaging 7.2 points, 4.0 rebounds, 1.4 blocks, and shooting a team-high 77 percent from the field.

[35] Fall made his debut for the Celtics on 26 October during a game against the New York Knicks at Madison Square Garden.

[41][42] On 30 December, Fall made his season debut for the Celtics, recording two points, a rebound, and two blocks in a 126–107 win over the Memphis Grizzlies.

[48] On 11 November, Fall made his debut for the Charge, logging a G League career-high 23 points along with 12 rebounds and three blocks in 29 minutes of play.

[49] On 22 December, Fall made his first career NBA start in a 111–101 loss to his former team, the Boston Celtics, where he grabbed a career-high 10 rebounds and a season-high four points.

[51] On 24 August 2022, Fall signed a one-year contract to play for the Xinjiang Flying Tigers of the Chinese Basketball Association.

[56] In September 2024, Fall joined the New Zealand Breakers of the Australian National Basketball League (NBL) for the club's three-game U.S.

[66] Prior to the 2019 NBA draft, Fall was viewed as a great shot blocker who was relatively lacking in lane agility and three-quarter-court sprinting speed.

[citation needed] Fall maintained a 4.0 grade-point average (GPA) in high school,[70] while taking advanced mathematics and science classes.