He proposed a halt to nuclear power projects in Finland in the wake of the Great Hanshin earthquake.

After the 2011 election, the Left Alliance became a partner in the six-party grand coalition cabinet led by Jyrki Katainen.

Being a football enthusiast, Arhinmäki became Minister for Culture and Sport and the party gained another ministerial portfolio as well.

The decision to join the government created a split in the party, leading to the expulsion of two MPs from the parliamentary group.

Later Arhinmäki became the subject of media criticism after a drinking binge at the Sochi Winter Olympics in February 2014.