Gender equality and the environment are important issues for Marin, who has also cited the importance of the welfare state.
In her 2019 election campaign she cited the importance of "equality, freedom and global solidarity," noting they are "the founding values of social democracy."
Marin was raised by a single mother who later was in a same-sex relationship with a woman. Marin has mentioned she experienced some stigma over their relationship. 
After completing her general upper secondary education in 2004, Marin took a Master's degree in Administration Sciences at Tampere University in 2017.
During her studies she was elected to the Tampere city council, which she chaired from 2013 to 2017.
In 2015, she was elected to parliament and served on several committees including for finance, legal affairs and the environment.
In June, Marin was named transport and communications minister in the government led by Antti Rinne, leader of the Social Democrats.
Marin has been deputy leader of the Social Democrats since 2014. Early this year she substituted for Rinne while he was on sick leave. The party - then in opposition - was gearing up for the April general election, and she received accolades for her confident manner and style.
In her spare time she enjoys being outdoors and being with friends and her family, and has thanked her husband for helping out with their daughter.
Marin is a fan of US band Rage Against the Machine, and also listens to classic hard rock, funk and old hip-hop, according to Tampere local daily Tamperelainen.
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