[1] Ulstein served as Bergen's city commissioner for social, housing and area investment from 2013 to 2014, when his party withdrew from the council cabinet, citing disagreements over a proposed route for the light rail to Åsane.

[6] Following his party's negotiations to enter the Solberg cabinet, Ulstein was appointed minister of international development on 22 January 2019.

ACT-A is set up to lead the efforts to mobilize political and financial support to ensure equitable distribution of corona virus vaccines, medicines and tests.

[8] Ulstein was considered one of the most leading candidates to replace Kjell Ingolf Ropstad as party leader after the resigned following a parliamentary housing scandal.

Ulstein never confirmed his candidacy, but still pulled himself out of consideration in October 2021, thereby leading to Olaug Bollestad being the presumptive new party leader.

[12] He became acting party leader following Bollestad's resignation following a formal complaint made against her by parliamentary staffers over her leadership style and behaviour.