In Lithuania he was coached by Jaak Salumets, ex-coach of Tallinn "Kalev" and the Estonia national basketball team.

After a successful season with the Lithuanian club Kullamäe came back to Estonia and played for Kalev and "Kamee" teams in Meistriliiga.

Kullamäe signed a contract with Telindus Oostende in 2000–01 season and won the Belgian League with the team.

After a serious knee injury and one season in an Estonian team "BC Hotronic" he moved back to Europe.

[3] In July 2009 he announced his retirement from active career and became an assistant coach in Tartu Rock.

[8] He resigned in December 2019 and became the assistant coach of BC Pärnu Sadam in February 2020.

His national team career-high score was 32 points, which was obtained during a match against Lithuania in autumn 1994, as part of the EuroBasket 1995 qualifying round.