Calling it his duty and responsibility to appoint a senator, the governor criticized the state Legislature for not passing a special election to fill the Senate post.
"If I don't make this appointment, then the people of Illinois will be deprived of their appropriate voice in the U.S. Senate," Blagojevich said while announcing Burris as his choice.
The embattled governor described Burris as a man of "unquestioned integrity" and a "distinguished senior statesman" with extensive experience. Standing side by side with the governor, Burris accepted the governor's appointment, saying he has nothing to do with the scandal surrounding Blagojevich.
During a flurry of questions at the news conference, Bobby Rush, a U.S. representative from Illinois, went to the podium to defend Burris.
"There is no African-American in the U.S. Senate," Rush said. "Thank God for this decision ... Roland Burris is worthy. He does not have one iota of taint."
Rush seemed to suggest racist motives for anyone who would try to stop Burris from taking office.
"I would ask you to not hang or lynch the appointee as you try to castigate the appointor," Rush said.
When reporters started shouting questions toward the governor, he went back to the podium to say he's "enjoyed the limelight" over the past couple of weeks, but doesn't want to hog it.
As he exited the room, the governor turned to reporters and again claimed his innocence, then made a botched attempt to repeat Rush's quote.
"Feel free to castigate the appointer, but don't lynch the appointer," he said.
Blagojevich has been under pressure to step aside or resign since his arrest earlier this month on federal corruption charges. He's accused of trying to sell President-elect Barack Obama's vacant U.S. Senate seat to the highest bidder.
In an interview in NBC Chicago's studio, Burris said he is "ready, willing and able to represent the 13 million people of our great state." [Watch the clip]
It's unclear if Blagojevich's appointment will be valid. Democrats in the U.S. Senate said any appointment by Blagojevich would not be seated. Late Tuesday, President-elect Obama backed their vow not to seat Burris.
In a videotaped announcement, Sen. Dick Durbin prefaced that his statements did not reflect on Burris personally, but he said it was a "serious mistake" for Blagojevich to exercise his power by making the appointment.
"What we saw today was an act of political defiance," Durbin said, and he again called upon Blagojevich to resign and allow Lt. Gov. Pat Quinn to lead the state.
Senate Majority Leader Harry Reid promised the Senate would not seat Blagojevich's appointment.
"It is truly regrettable that despite requests from all 50 Democratic Senators and public officials throughout Illinois, Gov. Blagojevich would take the imprudent step of appointing someone to the United States Senate who would serve under a shadow and be plagued by questions of impropriety. We say this without prejudice toward Roland Burris's ability, and we respect his years of public service. But this is not about Mr. Burris; it is about the integrity of a governor accused of attempting to sell this United States Senate seat. Under these circumstances, anyone appointed by Gov. Blagojevich cannot be an effective representative of the people of Illinois and, as we have said, will not be seated by the Democratic Caucus," Reid's statement read. "We again urge Gov. Blagojevich to not make this appointment. It is unfair to Mr. Burris, it is unfair to the people of Illinois and it will ultimately not stand."
Quinn -- the man poised to become governor if Blagojevich is impeached or resigns -- called the appointment an "insult to the people of Illinois."
Illinois Attorney General Lisa Madigan -- who made a failed attempt to have the state Supreme Court remove Blagojevich from office -- reiterated her call for the governor to step down.
"With today’s action, Governor Blagojevich, once again, fails to recognize his complete lack of credibility. This further demonstrates his inability to put the best interests of the People of Illinois first," she said.
Illinois Treasurer Alexi Giannoulias said that because of the allegations against the governor, the appointment process has "been tainted and will continue to be tainted as long as he holds office."
He reiterated his call for the Illinois General Assembly to move quickly with impeachment proceedings and remove Blagojevich from office.
"The question here is not whether Roland Burris would make a good Senator. The question is whether Blagojevich should have the right to make the appointment," Giannoulias said in a statement released Tuesday. "Regardless of whether he wanted to appoint Mother Theresa or Abraham Lincoln, I believe Blagojevich lost that right when he allegedly attempted to sell the Senate seat to the highest bidder. He abused his power and should lose his appointment power."
Secretary of State Jesse White moved to block the Burris appointment, saying he would refuse to sign any document from Blagojevich appointing a new senator.
"Although I have respect for former Attorney General Roland Burris, because of the current cloud of controversy surrounding the Governor, I cannot accept the document," White's statement read.
"Secretary White is a good friend of mine ... I think he will re-think his position once he understands his authority is really perfunctory," Burris said.
No surprise, Illinois Republicans also came out against the appointment.
"Blagojevich Democrat Roland Burris is emblematic of the old-school, pay-to-play culture that has plagued Illinois for generations and this appointment is another embarrassment for the people of Illinois," a statement from the Illinois GOP read. "Once again, Blagojevich Democrats have failed the people of Illinois by refusing to strip Rod Blagojevich of his senate appointment power and blocking a vote of the people."
But with traditional Blagojevich bravado, the governor said he is "absolutely confident and certain that the United States Senate will want a man of Roland Burris' integrity."
Burris is not without ties to Blagojevich. Between 2002 and 2006, his consulting firm contributed over $10,700 in money and in-kind donations to the governor's campaign war chest, according to the state Board of Elections. He and his wife gave $4,500 in private donations to Blagojevich between 2004 and 2008.