Since then, Brown has worked to repair his image, undergoing domestic violence counseling and rediscovering popularity with his hit album "F.A.M.E. (Forgiving All My Enemies)." Last year, his restraining order was eased. The former order required Brown to stay 50 yards away from 23-year-old Rihanna, but the restriction was reduced to 10 yards if they were at a music industry event.
On Sunday evening, Twitter was abuzz with questions of Brown's significant role in the proceedings. Many critics argued against the Grammys' decision to celebrate Brown and endorse his comeback.
New Yorker music critic Sasha Frere-Jones called Brown's return "one of the Grammys' weirdest choices ever," and cited R&B singer Drake as the more deserving star in the genre to celebrate.
In an op-ed, Valerie Strauss for The Washington Post said that while people deserve second chances, "That doesn't mean they deserve a chance to strut around the Grammy stage a few years after being convicted of felony assault."
Jeffrey Goldberg for The Atlantic tweeted: "I don't look for the Grammys for moral clarity, but, really? Do the words 'felony assault' mean anything at all?"
On Monday, Neil Portnow, president of The Recording Academy, defended Brown's role in the telecast, saying the Grammys ultimately proceed out of the academy's voting.
"That's really where the judgment comes from: music professionals listening to the music of other professionals," said Portnow. "Clearly, our voting membership rated highly Chris' musical work this past year.
"If we're going to get in trying to personally evaluate artists in terms of their personal lives, that's a slippery slope that we wouldn't want to get into," he added.
On Monday's "CBS This Morning" Grammy producer Ken Ehrlich said that he was "kind of rooting" for Brown.
"I just believe people deserve a second chance," said Ehrlich. "The year he had this year, really brought him back into the public. He really deserved a second chance."
Rihanna, who also performed Sunday, did not complain about Brown's attendance. She has said she's glad to see him succeed again.
Certainly, there are many fans of Brown - "Team Breezy," as he calls them - and they, too, took to social media to defend Brown. But some of those tweets were also held up as examples of questionable taste.
The site Buzzfeed gathered 25 tweets from Brown fans with lines such as: "I don't know why Rihanna complained. Chris Brown could beat me anytime he wanted to."
The feminism blog Feministe cited such reaction as evidence that "we as a society have a lot more work to do" to educate on domestic violence.
Rita Smith, executive director of the National Coalition Against Domestic Violence, also questioned the message the Grammys were sending.
"If an awards show is going to highlight an artist, what an awesome message they could send if we got an update somehow about how that artist had changed in a positive way," said Smith. "Otherwise, the message becomes wait for a period of time and go on with business as usual."
Brown, who didn't attend last year's Grammys even though he was nominated for three awards, has sometimes portrayed himself as embattled. On Sunday, he tweeted, "Team breezy we have come (a long) way ... No matter what anyone says ... WE MADE IT!!"
In his acceptance speech and performances, he made no mention or gesture to his last, abbreviated trip to the Grammys. But he did tweet - and then delete - the message: "People who make mistakes and learn from them are ROLE MODELS too. I'm just happy to inspire growth and positivity."
Rihanna also performed Sunday, singing her hit "We Found Love" and transitioning into a duet of "Princess of China" with Coldplay's Chris Martin. Rihanna was nominated for four awards, including best album for her disc "Loud." She shared in the wins for best rap/sung collaboration and best rap song for Kanye West's "All of the Lights," with Kid Cudi and Fergie.
But many performers watching at home questioned Brown's involvement.
"Are Chris Brown's mom and dad CBS and Grammy Brown?" sarcastically wondered Eric Stonestreet of "Modern Family."
The singer Michelle Branch tweeted: "Trying not to go off on a rant but ... Chris Brown ... (bites tongue) have we forgiven him?"
"View" co-host Sherri Shepherd took a similar tact, writing, "Looks like all is forgiven (with) Chris Brown. That's all I'll say."