U.S. Sen. Cory Booker, Newark's former mayor, announced on Twitter Friday morning that he is running for president of the United States.

Booker's announcement on the first day of Black History Month comes as no surprise. The 49-year old senator's run was years in the making. He recently stepped up his travel to early primary states, including in Iowa, New Hampshire and South Carolina.

Booker enters a growing field of Democrats vying for the 2020 nomination. Among those who have previously announced include fellow senators Elizabeth Warren of Massachusetts, Kamala Harris of California and Kirsten Gillibrand of New York.

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In his Twitter announcement, Booker returns to a theme that he once used with great fanfare during a 2009 State of the City address based on Maya Angelou's poem, "Still I rise," in which he declared, "Newark will rise."

"Together, America, we will rise," Booker declares in his video announcement.

In the video, Booker references his youth, when he says his parents tried to move the family to a neighborhood with great public schools, but realtors wouldn't sell his parents a home because of the color of their skin.

"A group of white lawyers who had watched the courage of civil rights activists were inspired to help black families in their own community, including mine," Booker said. Booker's family eventually moved into Harrington Park, a predominantly white suburb in Bergen County.

“The history of our nation is defined by collective action; by interwoven destinies of slaves and abolitionists; of those born here and those who chose America as home; of those who took up arms to defend our country, and those who linked arms to challenge and change it,” Booker said.

In the video, Booker explains how he ended up in Newark after going to Stanford University then the University of Oxford as a Rhodes Scholar before getting his law degree at Yale Law School.

"I moved into the Central Ward of Newark to fight slumlords and help families stay in their homes," Booker said.

Booker was first elected as a Central Ward Councilman in 1998. He challenged the incumbent Newark mayor Sharpe James in 2002, but lost. He put in a successful bid for mayor of Newark in 2006 and was re-elected in 2010.

As mayor, he was liked by some in Newark, but didn't have fans either. The current mayor of Newark, Ras Baraka, rallied against Booker in 2014, saying Booker divided the city to take power from people. Baraka also criticized the Booker saying he was never around when major decisions had to be made. 

The two have made amends now. Baraka came out in support of Booker in October after President Donald Trump said the now-presidential hopeful "ran Newark, New Jersey into the ground."

In 2013, Booker won a special election for the seat previously held by U.S. Sen. Frank Lautenberg, who died in office.

"I am the only senator who goes home to a low income, inner-city community, the first community that took a chance on me," Booker said on the video, which shows images of Booker in Newark, including getting a shave.

Essex County Executive Joe DiVincenzo, Jr., who has been a long time supporter of Booker, predicted he would be president.

“Over a year ago, I predicted Cory Booker would be our next president and I am overjoyed that he announced his candidacy today,” DiVincenzo said. “I have worked with Cory on the local and national levels and, no matter what the issue, his concern has always been about doing what is best for the public. His unique way of bringing people together, courage to work across party lines and passion to challenge what is wrong are the traits American needs in its next leader."