Associated Press/Bebeto Matthews
In this June 11, 2014 file photo, the eastern section of Rikers Island jail complex in the Queens borough of New York is shown.
"It will take many years, it will take many tough decisions along the way, but it will happen," de Blasio said.
De Blasio said a combination of crime reduction, alternative sentencing, and bail reform will lower the city's jail population rate significantly enough over the next decade to allow for the jail to be closed.
New York City currently has 9,500 people in custody, and must bring the number down to 5,000 before the jail can be closed, de Blasio said. He said the process will take 10 years at a minimum.
City officials are working under the assumption that "at least a few new facilities" will need to be built to accommodate the remaining inmates, de Blasio said, although he could not confirm how many will be required.
"I would argue the fewer the better," he said.
Local activist groups and criminal justice reform advocates have long been pushing de Blasio and other city officials to close the troubled complex.
The city settled in federal court in 2015, after a years-long federal investigation found that civil rights violations, violence and excessive force, and corruption were systemic problems at the jail.
De Blasio has previously called efforts to close the jail a "noble idea" but an ultimately unworkable one, due to the potential for a billion-dollar pricetag and a lack of other facilities to which inmates could be transferred.
De Blasio said at the press conference he now believes the jail's closure is attainable because of his recent conversations with city officials such as City Council Speaker Melissa Mark-Viverito regarding a more realistic timeline.
The officials ultimately came to the conclusion that a decade was the minimum period of time in which it could be done.
Mark-Viverito has been a vocal proponent of shutting down the complex, detailing in her State of the City speech last year the criminal justice reforms that would significantly bring down the jail's population.
"For too long Rikers Island has stood as a symbol of injustice in our city," Mark-Viverito said at the press conference.
New York Gov. Andrew Cuomo has also backed the jail's closing, just this month taking a jab at de Blasio for not taking action on the complex sooner.
"The city has said we can't do it, it's too hard. Impotence is not a defense for me," Cuomo said, according to the New York Daily News. "It is an outrage for New York City to allow a Rikers to exist."