Sen. Michael F. Bennet (D-Colo.) speaks during the North American Building Trades Unions Conference at the Washington Hilton in Washington, D.C., on April 10. (Zach Gibson/Getty Images)

Sen. Michael F. Bennet of Colorado, a champion of political moderation, announced Thursday that he would join the crowded Democratic presidential race.

Bennet announced in April that he had been diagnosed with prostate cancer. After surgery, he reported that it had been successful and he had no need for further treatment.

He made his announcement Thursday during an interview on the “CBS This Morning” program. He is the 21st major candidate to enter the primary.’

“My plan is to run for president,” Bennet said on CBS, adding that he will focus on issues including health care, economic mobility and the “need to restore integrity to our government.”

Bennet emphasized his track record of bipartisan legislation in Washington and said he would stand out among Democrats because of his ability to tell the truth, his record of winning elections in a “purple” state like Colorado and his history of turning around failing businesses in the private sector.

“I think I distinguish myself in a number of ways,” he said.

Bennet’s entry as a self-described “pragmatic idealist” adds yet another more-moderate face to a sprawling Democratic field that has been dominated for the first few months of the nomination race by more-liberal voices.

In his travels to Iowa and New Hampshire this year, Bennet has repeatedly called on Democratic voters to resist the lure of more ideologically extreme candidates in favor of a nominee who is positioned to reject pressure by its left wing.

“We’ve got to nominate somebody who can beat Donald Trump,” he said at a recent stop in Concord, N.H. “That means we have a responsibility not to do ourselves in.”

Bennet, 54, has called Medicare-for-all “a bad opening offer” to achieve broader health care coverage and prefers creating a public option for health coverage that could be offered in the current structure of the Affordable Care Act. He has been critical of liberal calls to pack the Supreme Court with more justices to counteract its current conservative-leaning majority.

Instead, his policy prescriptions have been more conventional, including calls for fiscal responsibility. He has co-sponsored legislation to expand the child tax credit and described the lack of economic mobility and growing economic inequality as the most pressing issues facing the country. A book he has written on his policy prescriptions for the country, including a vision for moving beyond its political polarization, will be released later this year.

He made headlines in January when he broke with his normal tone by angrily denouncing fellow Sen. Ted Cruz (R-Tx.) on the Senate floor for criticizing the last government shutdown, after previously leading an effort to shut down the government in 2013.

Bennet also criticized Trump in the speech for demanding $5 billion for “a medieval barrier on the border of Texas.”

“This is a joke,” Bennet thundered.

His critique of dysfunction in the U.S. Capitol is central to his political approach. During the Obama years, he referred to the nation’s capitol as the “Land of Flickering Lights” because the major accomplishments in Congress were limited to finding a way to keep the government open. And he has been a vocal opponent of the doctrinaire Freedom Caucus — a hard-line coalition of conservative and populist Republican lawmakers.

Born in New Delhi while he father was working for the U.S. ambassador to India, Bennet was raised in the District of Columbia and educated at St. Albans School. He went on to earn degrees from Wesleyan University and Yale Law School. His younger brother, James Bennet, the editorial page editor of the New York Times, vowed to recuse himself from any work related to the presidential election if his brother entered in the race.

The future senator showed an early interest in following his family’s calling in politics — his grandfather had been an adviser to Franklin D. Roosevelt, and his father also worked in the State Department and for several Democratic senators. In junior high school, Bennet worked as a Senate page. He later worked for then-Ohio Gov. Dick Celeste (D) and as an attorney at the Justice Department during Bill Clinton’s presidency, before relocating to Colorado in 1997.

There, Bennet worked as an investment adviser for Anschutz Investment, which is run by the conservative billionaire Philip Anschutz, a major Republican donor. He is the second politician from Colorado to enter the 2020 race, following former governor John Hickenlooper, whom Bennet previously worked for when Hickenlooper was mayor of Denver. Bennet later served as the superintendent of Denver Public Schools, before his appointment to the Senate in 2009 to fill a vacant seat he has held ever since.

“If you look at my career, it’s not been about plotting how to grab the brass ring or move up to the top of the ladder,” Bennet told The Washington Post in 2016. “I took jobs that a lot of people in similar situations wouldn’t have taken — in fact, a lot of them said I was crazy. And yet every one of those jobs powerfully informed the next job, or the one after that, in ways that I, certainly, could have never predicted.”

John Wagner contributed to this report.