From 2000 to 2003, he held the position of Director General at European Committee under the Government of the Republic of Lithuania, later serving as a lecturer at the Institute of International Relations and Political Science at Vilnius University from 2003 to 2004.

At the European Parliament he serves on the Committee on Foreign Affairs (AFET) and is chairing the delegation for relations with Afghanistan for his second term already.

2014-2019 term He was appointed as vice-president of the ALDE (Group of the Alliance of Liberals and Democrats for Europe) political faction for the period 2014–2017.

As a member of the Committee on Foreign Affairs, Auštrevičius was charged with assessing the European Union Association Agreement with Moldova for the Parliament.

[4] 2019-2024 term During his second term in the European Parliament, Petras Auštrevičius was a full member of the Committee on Foreign Affairs (AFET), a coordinator for the Renew Europe group in the EP Subcommittee on Security and Defence (SEDE) and was a substitute member of the EP Committee on Transport and Tourism (TRAN).

In 2015, news media reported that Auštrevičius was included in a Russian blacklist of prominent people from the European Union who are not allowed to enter the country.

In 2005, he co-founded and served as a president of a discussion Europos Klubas (English: European Club) at Seimas, founded Vilnius University Alumni Society of the Faculty of Economics.

He is the current co-chair that represents the European Parliament, and chairs together with Ivanna Klympush-Tsintsadze and Ostap Semerak on the side of Ukraine.