Kullas has also had second place finishes in the final overall standings in the ADAC MX Masters series and the Spanish Motocross Championship during his career.

[8] On the back of this, Kullas was signed to race in the MX2 class of the FIM Motocross World Championship full-time for 2010 by the Yamaha Gariboldi Monster Energy team.

[9] Unfortunately a knee injury obtained at the Swedish Grand Prix curtailed his season, resulting in an 18th in the final championship standings.

He remained with Sahkar KTM for that season, finishing in 18th in the MX2 World Championship standings after only competing in the European rounds of the series.

2015 would be Kullas' last year in the MX2 class, he started the season competing for the British-based Heads and all Threads Suzuki team – mainly concentrating on the British Motocross Championship.

Kullas had an immediate impact, placing third in the second race at the Latvian Grand Prix – a result good enough to give him his first overall world championship podium.

[14] He managed to finish in second in the final standings of the ADAC MX Masters championship, 12 points behind his teammate Dennis Ullrich.

[16] The 2019 Motocross des Nations saw Kullas play a part in Estonia recording another fourth position overall, equalling the previous best result in 2015.

In 2022, Kullas competed as a replacement rider for the Gebben Van Venrooy team in MXGP for four rounds, holeshotting a race in Lommel.

He competed in two MXGP rounds for the team, showing impressive speed on both occasions, including finishing eighth in the second race in Lommel.

[19] Despite missing the last round due to a dislocated shoulder, Kullas was able to finish second in the final AX Pro class standings.

Following this, he took his career to Brazil by signing for the KTM Pro Tork Racing Team for the Brazilian Motocross and Arenacross championships.