Born in Opatje Selo in present-day western Slovenia, Marušič studied law at Universities of Graz and Prague, where he graduated in 1911.

Then, as a member of the Yugoslav Committee he worked in Rome, in the United States, and finally in Paris, where he attended the 1919 Peace Conference[2] along with Ante Trumbić.

After the January 6th Dictatorship was established by King Alexander in 1929, first he was appointed to the Supreme Legislative Council, and in December 1930 Marušič was made Ban of the Drava Banovina province.

[2] Following the April 1941 Invasion of Yugoslavia he became a high-ranking member of the Liberation Front of the Slovene Nation (OF), and from 1942 he was interred in Italy.

From 1944 to 1945 he was justice minister in the Yugoslav government-in-exile of Ivan Šubašić, and later served in the unified government of the Democratic Federal Yugoslavia led by Josip Broz Tito until January 1948.