The 21-year-old spent last season on loan at FC St. Pauli, making 12 appearances in the Bundesliga and two in the DFB-Pokal. Wagner had previously been on a season-long loan at SpVgg Greuther Fürth in 2023/24, playing 31 Bundesliga 2 games and once in the DFB-Pokal.

During his youth, Robert Wagner played for SC Lahr and then SC’s academy. He was part of the U23 side that won promotion to the 3. Liga in 2021. He made 48 appearances in the third division for SC’s reserves. Wagner’s Bundesliga debut came in 2022 at SC, and he's played a total of four league games and one UEFA Europa League match to date for the first team. The midfielder has also won 22 caps at youth level for Germany, representing his nation at the U19, U20 and U21 age groups.

“Robert didn’t have the best of years in Hamburg due to injury,” said SC’s sporting director Klemens Hartenbach. “This move to Holstein Kiel will now give him the chance to get more minutes again. We will keep a close eye on his development.”