[3] At the end of his first season with the club, Weidemann helped the Bayern Munich U19 team win the junior championship, and was named MVP.

[8] Following the season, Weidemann moved to club Ratiopharm Ulm on a two-year contract entering the 2024–25 campaign.

[10] The following year, Weidemann was a member of the Germany U18 national team that reached the semi-finals at the 2016 FIBA U18 European Championship.

[12] A year later, Weidemann helped the Germany U20 national team win bronze at the 2018 FIBA U20 European Championship.

He was selected to the team for Germany's final two matches of their 2023 FIBA World Cup qualifying campaign.