House Democratic Leader Nancy Pelosi said Crowley had been an unwavering champion for America's working families for nearly two decades.
Ocasio-Cortez, who is 28 and hails from the Bronx, is expected to win the general election this fall against her GOP opponent in a deep blue district.
Those included New York Rep. Dan Donovan, who defeated convicted felon Michael Grimm in New York City's only Republican stronghold, and former Republican presidential nominee Mitt Romney, who once branded Trump "a fraud" but has warmed to the president in the past two years.
Ms Ocasio-Cortez, a former Bernie Sanders volunteer from a Puerto Rican family, won with 57.5 percent of the vote.
Sanders was elated on Wednesday after what transpired the previous evening in NY, and also in Maryland, where Ben Jealous, a progressive who previously chaired the NAACP, had won the Democratic primary for governor by more than 10 percentage points.
"I don't take a dime from corporations because I know it's the only way we get it done", she wrote later in the caption. She also wants to push for legislation that would require wealthy people and corporations who make large campaign contributions to disclose where their money is going.More news: Trump says Saudi king agrees to ramp up oil production
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"I think that no person should be homeless. if we can have public structures and public policy to allow for people to have homes and food and lead a dignified life in the United States", she told Colbert. But if the party falls short "there will be new leadership throughout".
Following Ms Ocasio-Cortez's win, dictionary Merriam-Webster tweeted that socialism emerged as their top search item. This time previous year, she was working as a bartender in the Bronx. "It is not to be viewed as something that stands for anything else", she said. They're going to have to explain why they are going to represent this caucus and what they're going to do to actually, you know, be a leader.
Crowley represents New York's 14th Congressional District, where he is also the leader of the Queens Democratic party.
At his concession speech, Mr Crowley played guitar, dedicating the song Born to Run by Bruce Springsteen to Ms Ocasio-Cortez.
A strong advocate of India-US relationship, Crowley was considered as one of the best friends of India in the House of Representatives. She had just one-tenth of the funds the incumbent had at his disposal, yet her radical progressive agenda clearly paid off. Pelosi kept her job, but the party-wide shakeup was already underway thanks to Bernie Sanders. Virtually every cell phone and house phone in the district was called, thousands of doors were knocked on, and multitudes of subway riders were greeted by campaign workers and the candidate herself. "We must unite, get engaged, and speak loudly with one, unified voice of freedom". And they're proving voters are ready for an unapologetic leftist message.
High rank in Congress means little to the folks back home, he said. So the truth of the matter is what we should be fighting for is getting to 218.