Clark faced off against Republican Robert Siano, who won just 14.1 percent of the vote compared to Clark's 85.58 percent, with 96.67 percent of scanners reporting, according to unofficial results from the city. About 33,000 people voted in the race.
"It has been incredibly inspiring to meet so many members of the community who are passionate about The Bronx," Clark said, "and I must say, I stand truly humbled that the voters have provided me with the opportunity to serve as the first woman District Attorney of our borough."
Clark will officially replace longtime Bronx District Attorney Robert Johnson on Jan. 1, who raised eyebrows when he announced in September that he planned on stepping down from his position to pursue a judgeship.
Johnson was nominated to be a New York State Supreme Court Justice in late September. He was the longest serving DA in Bronx history but was often criticized for his low conviction rate and the office's large backlog of cases.
He was also heavily criticized for the way he decided to step down from his office, as he did not announce his intention to seek a judgeship until after winning the Democratic primary, meaning his replacement candidate was chosen by party officials rather than voters. Good government advocates sharply criticized the move for its lack of transparency.
Clark worked in the Bronx DA's office from 1986 until April 1999, when she was appointed to be a judge for the New York City Criminal Court.
In 2004, she was appointed to be an acting judge for the New York State Supreme Court, and she became a designated associate justice in 2012 for the court's appellate division.
Clark has pledged to focus on increasing efficiency at the Bronx DA's office through measures like setting up a CompStat-style system to hold staffers accountable for dealing with cases quickly and establishing task forces to look through old indictments and misdemeanors.
Siano said he was disappointed with the election results but congratulated Clark on her victory and thanked his supporters, adding that he looked forward to serving the public going forward.
"I just put my name out there and gave it a shot and went all out," he said. "I can’t say I have any regrets. I did everything I could."