In 2012, Sinkevičius was a trainee in the Unit of Regional and Ethnic Affairs at the Office of the Prime Minister of the Republic of Lithuania.

In 2014, Sinkevičius worked as an international group project manager in Lietuvos paštas; in 2014–2015, he participated in the ‘Create Lithuania’ program.

[7] In the European Parliament Sinkevičius is serving as deputy chair of the Greens–European Free Alliance (Greens/EFA) group, under the leadership of co-chairs Terry Reintke and Bas Eickhout.

By contrast, Skvernelis claimed that Sinkevičius gave up his seat because the Foreign Minister position had not been assigned to DSVL.

[11][12] In 2018, Sinkevičius was awarded for The Best Solution for Better Business Environment of the Year by the association Investors’ Forum, and Blockchain Leadership at #SWITCH!

In 2019, he received the Partnership Leader 2018 award for innovation reform and development of startup ecosystem from the organisation Lithuanian Business Confederation.