Pressley is backed by Alexandria Ocasio-Cortez, the leftist socialist who defeated Crowley in NY on a message of pushing to "Abolish ICE".
Pressley represents the latest underdog candidate to have emerged to challenge both establishment Democrats and Republicans.
Pressley's win echoes the June primary in a safely Democratic New York City congressional district where first-time candidate Alexandria Ocasio-Cortez beat a 10-term incumbent, sparking enthusiasm for progressive candidates across the United States. In fact, Pressley was the first black woman elected to the city's council and now, running unopposed, will be the first black woman MA sends to Congress.
She was raised by her single mother, Sandra Pressley, on the north side of Chicago while her father, Martin Pressley, battled addiction and spent much of her childhood in prison.
During the race, Capuano raised $1.73m to Pressley's $890,000, actively campaigning against her and even cancelling his vacation as soon as he heard she was running.
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He thanked her for her friendship, noting that he knew it would continue beyond the time they had in Mexico. The pair reconnected on the newest season of Bachelor in Paradise but broke up on Monday evening's episode.
Pressley's campaign garnered national attention amid a summer of progressive challengers taking on - and sometimes defeating - Democratic incumbents.
Democratic congressional nominee Ayanna Pressley took a shot at President TrumpDonald John TrumpBrennan defends Kaepernick: He didn't kneel "to disrespect our flag" Trump warns Syria against attack on rebel stronghold: "Don't let that happen" Omarosa celebrates second week on bestsellers list despite "hit-pieces" from Trump allies MORE in her victory speech on Tuesday night.
"Everyone knows she gave me my roots to my wings", Pressley told the Herald.
However, two other Massachusetts Democrats, Reps. "Ayanna Pressley is going to be a good congresswoman", he said. He was buoyed by an advantage in campaign funds and a number of endorsements, including from Deval Patrick, the state's first African-American governor.