In September 2021, he set a new personal best in the javelin with a throw over 80 metres for the first time, throwing 80.11 metres in
Jena. At the end of that season he left his local club TuS Bergen to become a member of TSV Bayer 04 Leverkusen. He later moved from Bayer Leverkusen to LG Offenburg. In August 2022, Dehning was a silver medalist in the
javelin at the
2022 World Athletics U20 Championships in
Cali, Colombia. In August 2023, Dehning was a silver medalist at the
2023 European Athletics U20 Championships in
Jerusalem with a throw of 78.07 metres. This broke the
Steve Backley European U23 record of 89.58 metres - a world record at the time - which dated back to 1990. In June 2024, he competed at the
2024 European Athletics Championships in
Rome. He threw 80.52 metres in qualifying to reach the final. He threw 76.16 metres in the final to place twelfth overall. He competed in the javelin at the
2024 Summer Olympics in
Paris in August 2024, throwing 79.24 metres to finish twenty second in the qualifying round, and did not proceed to the final. He won the javelin at the German Winter Throwing Championships in Halle in February 2025, with a throw of 79.61 metres. He competed in May 2025 at the
2025 Doha Diamond League. == References ==