"I rise with the intention of disrupting the normal business of the United States Senate for as long as I am physically able," Booker said at the beginning of his marathon speech at around 19:00 local time on Tuesday evening.
"I rise tonight because I believe sincerely that our nation is in crisis."
Although Booker's speech was not a filibuster, a speech designed to obstruct passage of a bill, it held up legislative business in the Senate on Tuesday.
The 55-year-old, who is the fourth-ranking Democrat in the chamber, filled some of the time reading letters from constituents, who said they had been harmed by President Donald Trump's policies.
He also ran out the clock by discussing sports, reciting poetry and taking questions from colleagues.
"I, first amongst us all, really love to speak," the former presidential candidate joked less than an hour before breaking the record.
As he reached the milestone, Booker said: "I want to go a little bit past this and then I'm going to deal with some of the biological urgencies I'm feeling."
The rules for such speeches require him to stay standing and forgo bathroom breaks.
The African-American senator also spoke of his roots as the descendant of both slaves and slave-owners.
"I'm here because as powerful as he was, the people are more powerful," he said, referring to segregationist Thurmond's record-setting address 68 years ago.
Booker's speech is also the longest seen in the Senate since a 21-hour filibuster in 2013 by Texas Senator Ted Cruz, a Republican, against Obamacare.
The Democratic party, currently out of power in the White House, Senate and House of Representatives, rallied behind Booker's symbolic act of protest.
"I just want to thank you for holding vigil for this country all night," Senator Raphael Warnock told Booker on the floor.