[5] Coached by Lorenzo Magri, Angelina Turenko, Alisa Mikonsaari, and Eva Martinek, Kessler made his international debut for Croatia at the 2020 CS Budapest Trophy, where he placed seventh.

[6] In January, Kessler competed at the 2022 European Championships in Tallinn, Estonia, finishing thirty-first in the short program, failing to advance to the free skate segment.

In February, he took bronze at the Merano Ice Trophy, silver at the Jegvirag Cup, and placed fifth at the 2021 Bellu Memorial.

[7] Going on to compete at the 2023 European Championships in Espoo, Finland, Kessler qualified for the free skate segment after finishing nineteenth in the short program.

In December, Kessler placed eleventh at the 2023 CS Golden Spin of Zagreb before winning his third national title at the 2024 Croatian Championships.

[6] One month later, Kessler competed at the 2024 European Championships in Kaunas, Lithuania, where he placed twenty-seventh in the short program and did not advance to the free skate segment.