[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/01/15/art.burrisin0115.gi.jpg caption="Roland Burris was sworn in to the Senate Thursday afternoon."]
WASHINGTON (CNN) - Veteran Illinois politician Roland Burris was sworn in as the junior U.S. senator from Illinois on Thursday afternoon, following an extended political battle to claim the seat.
Watch: Burris becomes a senator
After being denied entry into the hallowed chamber last week, Burris was warmly welcomed Thursday by Senate colleagues, including Majority Leader Harry Reid.
"Whatever complications surrounded his appointment, we made it clear from the beginning, both publicly and privately, that our concern was never with Mr. Burris," Reid said. "I didn't have the pleasure of meeting Mr. Burris until last week. I found now-Senator Burris to be engaging, gracious, and he was very firm in his commitment to become a good and effective United States senator.
"Given the uncertainty around his appointment, all of his statements and actions, again both publicly and privately, reflected his strong character that will serve him well as be begins his service to the people of Illinois," Reid added.
Some Senate Democrats had argued that Burris should not be seated because he was appointed by embattled Illinois Gov. Rod Blagojevich to fill the junior senator position vacated by President-elect Barack Obama.
Blagojevich was arrested in December on federal corruption charges. Among other allegations, federal prosecutors said the governor tried to trade or sell Obama's vacant Senate seat.
The governor was impeached on corruption charges by the Illinois House of Representatives, and now faces a trial in the state Senate.
Before his swearing-in, Burris spoke of vindication.
"It's called faith. And we knew that we were in the right. The law was on our side. And all we had to do was prevail," he said of his fight to claim his seat.
"As a matter of fact, I will go to work this evening. There will be votes taken tonight and tomorrow. The family will be coming back tonight (to Chicago). But I will have to go to work," Burris said as he left Chicago's O'Hare airport Thursday morning with his wife.
The senior senator from Illinois, Dick Durbin, also welcomed Burris to the Senate, speaking of his rise and their shared origins from railroad families.
"Roland Burris paved the way for so many to follow, including the man who will be sworn in as president next Tuesday, Barack Obama," Durbin said. "He's held two our state's highest elected offices. He was Illinois' first African-American comptroller, as well our first African-American attorney general. Roland Burris is a good man and a dedicated public servant. And that's why he's returned to public life."
In refusing to seat Burris last week, the U.S. Senate cited a 125-year Senate rule requiring the secretary of state's signature to certify an appointment. Illinois Secretary of State Jessie White refused to sign the certificate due to the controversy.
But the Illinois Supreme Court ruled Friday that White's signature was not necessary for the certificate to be valid.