Lončar started his career at Radnički Kragujevac and later joined Partizan, making his professional debut in 1989.

Lončar also played for Real Madrid, Cagiva Varese, PSG Racing, Maccabi Tel Aviv, Joventut Badalona, Zucchetti Montecatini, Breogán, Estudiantes and Armani Jeans Milano.

Lončar was a member of the Yugoslav national team at four major tournaments during the 1990s.

After ending his basketball playing career in 2006, Lončar began working on Spanish television as a studio analyst for the NBA coverage on Movistar+ platform.

In March 2018, Lončar was named a sports director of Partizan NIS.