In 2005, Motiejūnas began his career playing with Žalgiris Kaunas' junior team, Žalgiris-Arvydas Sabonis school, who play in the Lithuanian National Basketball League.
In 2007–08, he made his debut for the senior team in a Baltic League game against the ASK Riga.
He scored 15 points in 22 minutes.

In 2008, Motiejūnas signed with Aisčiai Kaunas for the 2008–09 season where he went on to average 19.9 points and 7.0 rebounds in 29.3 minutes per game, and he scored a season-high 29 points in a Lithuanian League game against Nevėžis on March 22, 2009.
In 2005, Motiejūnas began his career playing with Žalgiris Kaunas' junior team, Žalgiris-Arvydas Sabonis school, who play in the Lithuanian National Basketball League. In 2007–08, he made his debut for the senior team in a Baltic League game against the ASK Riga. He scored 15 points in 22 minutes.
In 2008, Motiejūnas signed with Aisčiai Kaunas for the 2008–09 season where he went on to average 19.9 points and 7.0 rebounds in 29.3 minutes per game, and he scored a season-high 29 points in a Lithuanian League game against Nevėžis on March 22, 2009.
Donatas Motiejūnas