[5][6] After trying and failing to draw interest from a National Basketball Association (NBA) team, Karnišovas began playing overseas.

His former college coach, P. J. Carlesimo, attributed his inability to play in North America to insufficient scouting and a more guaranteed financial return in Europe.

Karnišovas is one of the few players to have played in Europe's four strongest national domestic league championships, Spain (for FC Barcelona), Italy (Fortitudo Bologna), Greece (Olympiacos Piraeus), and France (Cholet).

[6][8] Karnišovas helped lead the senior men's Lithuanian national basketball team to consecutive bronze medals at the Summer Olympic Games in 1992 and 1996.

[18] Two days later, on June 15, 2017, the Nuggets made Karnišovas their new general manager, with Tim Connelly moving up to become the team's president of basketball operations.

[19][20] The Bucks would eventually promote their director of basketball operations, Jon Horst, for their vacant general manager position instead.