Roland Burris, sounding a triumphant note Tuesday, said Democratic leaders were swayed to seat him in the U.S. Senate because they knew he had the qualifications and the Constitution in his favor.
"We didn't want Illinois to be caught up in a situation as difficult as times are now with only one senator," Burris told FOX News. "So it would be fair to the state to have someone who can learn the procedures and rules and hit the ground running with issues that we will be facing."
"As things evolved, they saw that I was a legal appointment and that I was prepared, ready, willing and able to go," he added.
U.S. Senate officials on Monday certified Burris to fill the seat vacated by President-elect Barack Obama and Senate Democratic leaders said they expect to seat the next Illinois senator on Thursday.
Durbin, the senior senator from Illinois, said he was looking forward to working with Burris, whom he said has a great reputation in the state, great experience as a politician, and would make a good senator.
At a press conference Monday afternoon, Burris said that he was "humbled and honored" to be on his way to the Senate floor.
"I'm thankful for the opportunity to serve," Burris said.
The decision, if carried out later this week, effectively draws to a close the contentious court filings and political stand-offs that had characterized his appointment.
"The secretary of the Senate has determined that the new credentials presented today on behalf of Mr. Burris now satisfy Senate Rules and validate his appointment to the vacant Illinois Senate seat," Senate Majority Leader Harry Reid said in a statement with his No. 2, Illinois senior Sen. Dick Durbin.
"Accordingly, barring objections from Senate Republicans, we expect Senator-designee Burris to be sworn in and formally seated later this week. We are working with him and the office of the vice president to determine the date and time of the swearing-in," they said.
The statement followed a meeting between Burris' lawyers and the Senate leaders. Burris dispatched his attorneys to the Capitol with formal paperwork designed to persuade Democrats to accept his appointment.
Durbin talked to Burris to congratulate him, he told FOX News. Reid was to do so later in the day, according to Reid spokesman Jim Manley.
"I congratulated him and he was stunned," Durbin said.
The scandal-tainted standoff had stretched into the new Congress' second week in session, serving as a distraction for Democrats trying to start the year off right and tackle an ambitious agenda.
Illinois Gov. Rod Blagojevich, under investigation for allegations that include seeking to trade Obama's Senate seat for personal favors, surprised Senate Democrats over the holiday break when he appointed Burris to succeed Obama in the Senate.
Senate Democrats, who had worried that any appointee would be tainted by Blagojevich, have been grappling with how to proceed ever since. They rejected Burris last week only to reverse course a day later after Obama himself privately weighed in and senators fretted that the situation was diverting their focus.
Illinois Republican Party Chairman Andy McKenna said the decision to seat Blagojevich's choice, "Democrats chose to trust a madman over the people of Illinois."
"Today's endorsement of Rod Blagojevich's handpicked choice for U.S. Senate confirms what Republicans have been saying for years -- that Illinois is in dire need of change," he said.
The Illinois Supreme Court ruled last week that under state law, Burris' appointment paperwork is valid and that it's up to the Senate to decide whether to seat him.
But Reid and other Democrats have said that unless the appointment is signed by both the governor and the Illinois secretary of state, it violates Senate rules.
Reid has said the Senate would vote on whether to seat Burris after Senate lawyers review the documents and Burris' testimony before an Illinois House impeachment panel in which Burris said he promised Blagojevich nothing in exchange for the seat.
Asked why Reid reversed himself about requiring a Senate vote on whether to seat Burris, Manley said "because Republicans decided not to force the issue. We had every reason to believe that Republicans would not let this go smoothly."
FOX News' Trish Turner and The Associated Press contributed to this report.