Loretta Lynch was officially sworn in Monday as the next U.S. Attorney General.
Lynch becomes the first black woman to serve as the nation's top law enforcement official.
Vice President Joe Biden led the ceremony at the Justice Department.
Lynch, 55, thanked her family and above all her father.
"Without him, I would not be standing before you today, having just been sworn in as the 83rd Attorney General of the United States of America just one week after his 83rd birthday," Lynch said.
"Your dad always taught you to stand up for whats right, speak out for what's just, get up when you get knocked down and move on. If there's anything you should know about Loretta Lynch following her father's example she excelled in everything she's done since she was a child. She's never been limited by the low expectations of others," Biden added.
Lynch was confirmed by the Senate last week.
She was nominated by President Barack Obama in November.
But her confirmation was held up by partisan disagreements over an anti-sex trafficking bill and Lynch's support for the president's executive actions on immigration.
Lynch formerly served as U.S. Attorney for the Eastern District of New York.
She replaces Eric Holder, who had served as U.S. Attorney General since 2009.