Between 1996 and 2001, he worked as a lawyer for CWL Telesport and Marketing AG (later known as Infront Sports & Media).

Concurrently between 2009 and 2013, Grimm also worked in various positions for FIFA, UEFA, and EFPL as well as on the board of directors for the small Swiss football team FC Biel-Bienne.

Later he also worked as a legal adviser for the Ukraine national football team during the Euro 2016 and for the Football Federation of Ukraine on questions regarding the final match of the 2017-18 UEFA Champions League at Olimpiyskiy National Sports Complex.

In 2018 Grimm was elected as the president of the Ukrainian Premier League by majority of votes.

[2] Grimm's contract expired on 5 April 2020 and he expressed no interest to run for another term,[3][4] however due to the ongoing COVID-19 pandemic elections were suspended and governing of the league was taken over by its general director until next elections.