In September 2014, Owen started his professional career overseas at Macedonian
Adriatic League team
MZT Skopje, at the time coached by
Zmago Sagadin. His contract was terminated by mutual agreement in March 2015, after a prognosis that a full recovery from an already lengthy back injury of his would last longer than previously expected. On July 31, 2015, Klassen signed with
Phoenix Hagen. On December 1, 2015, Owen was named German BBL Round 10 Player of the Week following an impressive 17 point, 10 rebound performance in a win over EWE Baskets Oldenburg. On May 2, 2016, he re-signed with Hagen for one more season. On December 8, 2016, he left Hagen and signed with Montenegrin club
Budućnost Podgorica for the rest of the season. On August 3, 2017, Klassen signed with the
Greek League club
PAOK. On December 21, 2017 PAOK announced the end of their corporation. The same day he signed with German club
s.Oliver Würzburg. On July 27, 2018, he signed with
Riesen Ludwigsburg. In July 2019, Klassen signed with the
Antwerp Giants. During the 2019-20 season, he averaged 10 points and six rebounds per game. On August 13, 2020, he signed with
Boulazac Basket Dordogne of the
LNB Pro A. On August 13, 2021, he has signed with
Löwen Braunschweig of the
Basketball Bundesliga. On July 19, 2022, he has signed with
EWE Baskets Oldenburg of the
Basketball Bundesliga. On June 24, 2025, he signed with
Rostock Seawolves of the
Basketball Bundesliga (BBL). ==Career statistics==