Gov. Andrew M. Cuomo of New York said on Tuesday that he would resign from office, succumbing to a ballooning sexual harassment scandal in an astonishing reversal of fortune for one of the nation’s best-known leaders.

Mr. Cuomo said his resignation would take effect in 14 days. Lt. Gov. Kathy Hochul, a Democrat, will be sworn in to replace him, becoming the first woman in history to occupy New York State’s top office.

“Given the circumstances, the best way I can help now is if I step aside and let government get back to governing,” Mr. Cuomo said in remarks streamed from his office in Midtown Manhattan. “And therefore, that’s what I’ll do.”

Mr. Cuomo’s dramatic fall was shocking in its velocity and vertical drop: A year ago, the governor was being hailed as a national hero for his steady leadership amid the coronavirus pandemic.