[1][2] N'Diaye, a center, was named Big West Conference Defensive Player of the Year after the 2013–14 NCAA Division I men's basketball season and earned all-conference honorable mention accolades as well.

In 2010, Amadou Koundoul, who was the assistant coach for the UC Irvine Anteaters men's basketball team at the time, saw N'Diaye participate in a pick-up game in a gymnasium at Dakar.

[7] After experiencing headaches upon his arrival to the U.S., N'Diaye saw a doctor and it was discovered that he was suffering from a golf ball-sized tumor in his pituitary gland, which had caused gigantism and was threatening his vision.

A married couple who lived in Huntington Beach, California, a city close to N'Diaye's future school, offered to become his guardians to ease his commute for medical treatments.

[6][8] Prior to participating in sports, N'Diaye attended Stoneridge Prep in Simi Valley, California, who steered him through his early years in the United States.

The school had a history of producing high-caliber international basketball players, including Enes Kanter and Nikola Vučević.

However, N'Diaye was not allowed to play the sport during his first year in the high school because of California Interscholastic Federation rules.

ESPN analysts commented on N'Diaye's basketball talent by saying, "Ndiaye is a legit 7-foot-5 prospect with extraordinary length and huge hands.

"[15] N'Diaye made his collegiate debut on 8 November 2013 against Fresno State with 5 points, 4 rebounds, and 1 block as the starting center.

[16] When the Anteaters defeated the Washington Huskies men's basketball team on 14 November 2013, N'Diaye recorded a season-high 18 points.

[18] In January, in a game at rival Long Beach State, coach Dan Monson told reporters that he believed his team was still afraid to attack the paint even when N'Diaye was sitting on the bench.

[20] Following the year, he was labeled a future top prospect by Kevin Pelton of ESPN.com, strongly due to his performance against Washington, in which he broke the school record for blocks for a single game.

[23] In mid-April 2015, N'Diaye made it official that he would forgo the 2015 NBA draft and return to UC Irvine for his junior year.

"[26] Following his second season with the Anteaters, websites such as CBSSports.com considered him a player that would need to play in the NBA Development League before joining a National Basketball Association roster.

He faced fellow Senegalese 7 ft 6 in (2.29 m) player Tacko Fall in the tallest tip-off and match-up in US college basketball history in a game against the UCF Knights.

[32] He was later named to the Senegal national basketball team's preliminary squad for the FIBA Olympic Qualifying Tournament in Manila.

[40] Standing seven feet, six inches tall and weighing 300 pounds, N'Diaye's wingspan (fingertip-to-fingertip reach) was measured as 8 ft 1 in (2.46 m) at the 2012 edition of the Amar'e Stoudemire Skills Academy.

[4] N'Diaye's skill set was often considered "raw" in high school, and received comments from Brethren Christian head coach, Jon Bahnsen, who said, "Right now his game is basically catch, turn, drop-step, dunk.

[44] During the 2016 tournament season, a writer for SB Nation wrote that "When Columbia guards find themselves one-on-one with just his frame between them and the rim, they reverse direction and scurry away, like terrified Tokyoites who just heard Godzilla stomping around.

"[45] In the past, N'Diaye has been compared with players such as Yao Ming and Rudy Gobert, who respectively stand 7'6" and 7'1" (2.29 m and 2.16 m) and feature a similar wingspan.

In their first-round match up, he helped the Champions to a 78–74 victory over the Talladega Knights; a team led by former NBA players Josh Boone and Gary Forbes.