He's been in charge of the city's public schools for nearly three years and led the nation's largest school district through the coronavirus pandemic.
"This is a very bittersweet moment for me," Carranza said. "I came here with the mission to lift up all of our public school children, not just some, all."
He said that he was stepping down to take the time to grieve the many COVID losses in his family.
"I am a New Yorker, not by birth, but by choice. A New Yorker who has lost 11 family members and close friends to Covid. And a New Yorker who quite frankly needs to take time to grieve," he said.
"It has been the honor of a lifetime to serve as chancellor," Carranza added.
Mayor Bill de Blasio thanked Carranza for his service and promised that there would be "better days ahead."
RELATED: NYC Schools middle schools reopen for in-person learning
Carranza actually drafted a resignation letter earlier this month but did not resign.
It is the second high-profile resignation that was apparently the culmination of a long-standing dispute with the mayor over the direction of the agency.
Just last August, Health Commissioner Dr. Oxiris Barbot, left the administration, in the middle of a pandemic.
"Richard Carranza was a real partner in our efforts to open school safely. Too often he had to fight behind the scenes to keep the needs of students, staff and their families ahead of politics. We wish him well. He will be missed," UFT President Michael Mulgrew said in a statement.
The Department of Education announced Carranza will be replaced by Bronx Executive Superintendent Meisha Porter.
She is a New York City public school graduate, a 20-year veteran employee, who has led at every level in the system. Porter will be the first Black woman to serve in the role. She will begin as Chancellor on March 15, 2021.
"We have successfully partnered with Meisha Ross Porter on projects in the past, including the Bronx Plan and expanding community schools. We look forward to working with her in the future," Mulgrew said in a statement.
Porter was born in Queens, New York and comes from a family of educators. She was raised by a single mother who returned to school to finish her degree and become an educator herself; "her upbringing has taught her the power of public education, and the difference one teacher can make," a press release by the city noted.
"To all the little girls out there, I'm saving a seat for you," Porter said while she gave a statement on Friday about accepting the position.
* Get Eyewitness News Delivered
* More New York City news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube