Martin J. Walsh was born in Boston in 1967, in the Savin Hill area of Dorchester, to first-generation Irish immigrants. He was diagnosed with cancer when he was seven, forcing him to miss many years of elementary school while undergoing chemotherapy to fight the disease, eventually prevailing in his struggle at the age of eleven when CAT scans showed no trace of the cancer left in the body.

At the age of 21, Walsh joined the Laborers Local 223 Union, serving as the president of the organization until his election to become mayor. He was also elected secretary-treasurer and and general agent of the Boston Metropolitan District Building Trades Council in 2010, a union umbrella group, and being named head of the Boston Building Trade in 2011.  

In 1997 Walsh was elected to the Massachusetts House of Representatives as the rep from the thirteenth district of Suffolk County, covering much of Dorchester and one precinct in Quincy. He was the Chairman of the Committee on Ethics, and served as a Co-Chair of the Massachusetts Democratic Party Labor Caucus. During his tenure he also served as the co-chair for the Special Commission on Public Construction Reform.

In 2013 he ran to become the Mayor of Boston, campaigning mainly on the issue of a 24-hour T, and beating out competitor John Connolly in the general election in November to win the seat. In his first term Mayor Walsh became known for his keeping of Boston as a sanctuary city, fighting for immigrant’s rights and safety. In the 2017 mayoral election against Tito Jackson, Walsh won in a landslide, with an almost 2:1 margin.