NJ lieutenant governor dies unexpectedly from undisclosed medical issue

New Jersey Lt. Gov. Sheila Oliver died Tuesday, one day after she was rushed to the hospital for an undisclosed medical issue.

"It is with incredible sadness and a heavy heart that we announce the passing of the Honorable Sheila Y. Oliver, Lieutenant Governor of the State of New Jersey," the Oliver family said in a statement. "She was not only a distinguished public servant but also our cherished daughter, sister, aunt, friend, and hero."

Oliver was 71 years old.

She had been serving as acting governor with Gov. Phil Murphy on vacation. The Democratic Senate President, Nicholas Scutari, took over as acting governor when Oliver was rushed to the hospital Monday.

Murphy remembered Oliver as a "trailblazer" in announcing her death.

"When I selected her to be my running mate in 2017, Lieutenant Governor Oliver was already a trailblazer in every sense of the word," Murphy said in a statement. "She had already made history as the first Black woman to serve as Speaker of the General Assembly, and just the second Black woman in the nation's history to lead a house of a state legislature. I knew then that her decades of public service made her the ideal partner for me to lead the State of New Jersey. It was the best decision I ever made."

The chairperson of the Democratic National Committee, Jaime Harrison, said he was "devastated" by Oliver's death, calling her someone who "exemplified the very best of what a public servant should be -- humble, selfless, and always looking to extend a hand to those who needed it most."

"She was the first Black woman to serve as speaker of the New Jersey General Assembly -- the second Black woman in our country to lead a legislative chamber -- and the first woman of color elected to statewide office in New Jersey. She will be greatly missed, but I have no doubt that her legacy will live on in the lives she touched through her lifetime of service," Harrison said in a statement.

Former New Jersey governor and 2024 presidential candidate Chris Christie tweeted, "It is a sad day for NJ and for me personally."

"I will miss Sheila. She served as Speaker in my first term and we treated each other with kindness and respect," Christie said. "She was a great person and partner."

ABC News' Fritz Farrow contributed to this report.