In 2011, Šehović became a member of déi gréng. When the SREL scandal came to light in Luxembourg in 2012–2013, Šehović followed the political debates and Parliament's inquiry committee and commented the process in his own political blog. In the same time, he became member of déi jonk gréng, where he campaigned for reform of the Secret Service law and snap elections. From 2013 to 2017, he was a member of the board of déi jonk gréng. In 2017, he ran for spokesperson and held this mandate until February 2020.[2]
In 2013, at the age of 22, Šehović became Head of Office and spokesperson for Claude Turmes, Member of the European Parliament.[3] As a policy advisor, he supported legislative work on several EU directives and regulations in the areas of environmental, climate, industrial and trade policy (e.g. the EU Circular Economy Package, Right2Water, CO2 emission standards for new passenger cars) and assisted the MEP's work in the European Parliament's Committee of Inquiry to investigate the VW diesel scandal.
In 2017, Šehović supported Claude Turmes' work on a book about the European energy transition.
After Claude Turmes moved into national politics, Šehović entered the 2019 European elections as the lead candidate of déi gréng, together with Tilly Metz.[4] Finishing seventh, he narrowly missed entering the European Parliament.[5]
After Christian Kmiotek announced his resignation from the position of party chair,[6] Šehović was elected by the Green Party's Congress on 9 July 2020 to succeed him as party leader. At the party congress on 20 March 2021, he was re-elected for another three years at the party leadership, together with Djuna Bernard.[7]