After the NBA's lockout ended, he tore his ACL during a condensed training camp and spent the entire 1999 season on the injured list.

The Mavericks invited Sesay back to camp in 2000 but early in the preseason was dealt along with guard Dana Barros to Detroit for forward Loy Vaught.

Playing for the NBDL's best team, Sesay displayed a multitude of talents and was one of the league's leaders in several categories, including scoring, rebounding, and assists.

He was named first-team all-NBDL and the league's inaugural MVP,[3] but the highpoint of Sesay's season had to be when he was called up on a 10-day contract by the Seattle SuperSonics on March 29, 2002, as injuries ravaged their roster.

When the second season started, the return to health of forwards Rashard Lewis and Vladimir Radmanovic put Sesay on the bench for only garbage minutes in the series' first games.

[4] Ansu Sesay impressed enough during his eight-game stint with the Sonics, on a 46.3% shooting, that he made his way onto the team's playoff roster and was part of Nate McMillan's postseason rotation.

After the season, the Sonics re-signed the restricted free agent to a two-year deal, and Sesay was expected to be a part of the team's rotation.

In addition to the three positions mentioned above, the Sonics coaching staff also discussed playing Sesay at the point when backup Kenny Anderson was injured during the early part of the 2002–2003 season.

In 2007–08, Sesay signed with another Italian team, Armani Jeans Milano, where he wore jersey number 4 and averaged 10.5 points, 4.9 rebounds and 1.4 steals in 14 Euroleague games.

In August 2008, ALBA Berlin inked power forward Ansu Sesay to a one-year deal, with an option to extend it until the end of the 2009–10 season.