Mallory, the co-founder the Women's March, appeared on stage with rapper Lil Baby during his performance of The Bigger Picture.
Surrounded by protesters, holding placards, she said: 'It's a state of emergency. It's been a hell of a year. Hell for over 400 years. My people, it's time we stand. It's time we demand the freedom that this land promises.
For his #Grammys performance, the Atlanta rapper Lil Baby was joined onstage by the activist Tamika Mallory and the rapper and community leader Killer Mike. It was one of many moments that centered Black artists. https://t.co/z7W6AOWYBx pic.twitter.com/nLJXHCCzrr— The New York Times (@nytimes) March 15, 2021
'President Biden, we demand justice, equity, policy and everything else that freedom encompasses, and to accomplish this, we don't need allies. We need accomplices.
'It's bigger than black and white. This is not a trend, this is our plight. Until freedom.'
Lil Baby's set recreated events seen across the US in the summer during the Black Lives Matter protests, which saw protesters and police clash in violent scenes that sparked accusations of police brutality on one side and rioting on the other.
His 'The Bigger Picture' performance also included a scene of a black man getting shot by a police officer. At one point, the rapper stood in front of an officer with riot shield and a building burned behind him as he performed on top of a cop car.
The artist's performance also featured a scene in which a black man was seen being arrested by two white 'police officers', alluding to the killing of George Floyd last year and other cases of perceived excessive force by police against black people.
The song's lyrics include 'too many mothers that's grieving' and 'they killing us for no reason...been going on for too long to get even'.
The death of George Floyd at the hands of Minneapolis police last May prompted hundreds of thousands of Americans to take to the streets in protest amid renewed calls for racial equality.
Biden on Saturday reiterated plans for 'meaningful police reform in Congress'.
Mallory, who also helped to found activist group Until Freedom, had on Saturday been at the a demonstrations in Louisville, Kentucky to commemorate the first anniversary of Breonna Taylor's death.
Taylor was shot dead during a botched police raid on her home on March 13, 2020.
Hundreds of activists also took to the streets in Los Angeles for a march on Saturday night, where two demonstrators were seen smashing a squad car.
President Joe Biden on Saturday had declared his support for police reforms.
'Breonna Taylor's death was a tragedy, a blow to her family, her community, and America,' he tweeted. 'As we continue to mourn her, we must press ahead to pass meaningful police reform in Congress.' Biden tweeted.
He added: 'I remain committed to signing a landmark reform bill into law.'
House Democrats earlier this month moved to pass the most ambitious effort in decades to overhaul policing nationwide. The George Floyd Justice in Policing Act was approved 220-212 March 3.
The sweeping legislation, which was first approved last summer but stalled in the Senate, was named in honor of Floyd.
The bill, which now heads to the Senate, would ban chokeholds and 'qualified immunity' for law enforcement and create national standards for policing in a bid to bolster accountability.
Harlem based campaigner Mallory was pictured at the protest in Jefferson Square Park. She was recognized on the Time 100 list in 2017; her book 'State of Emergency' takes it name from her speech last summer.
Lil Baby had been nominated for Best Rap Performance and Best Rap Song.
In September last year Mallory criticized Kentucky Attorney General Daniel Cameron, over a grand jury's decision not to directly charge officers in Taylor's killing.
'Daniel Cameron is no different than the sell-out N**roes that sold our people into slavery and helped white men capture our people to abuse them and to traffic them,' she said. 'That is who you are Daniel Cameron.
'You are a sell-out, and you were used by the system to harm your own mama, your own black mama,' she continued. 'We have no respect for you, no respect for your black skin because all of our skinfolk ain't our kinfolk and you do not belong to black people at all.'
Cameron - Kentucky's first black attorney general - is considered to be a rising star in the Republican party.
Taylor's mother Tamika Palmer led the peaceful protest in Louisville Saturday.
It consisted of hundreds marching behind a large purple banner with an illustration of Taylor's face, chanting 'No justice, no peace.'
'Eyes are on Louisville, Kentucky, today so let's show America what community looks like,' said Taylor´s aunt, Bianca Austin, who wore her niece´s emergency medical technician jacket.
Austin spoke from a stage set up in Jefferson Square Park, which became an impromptu hub for protesters during months of demonstrations last summer.
A grand jury in September recommended no homicide charges against the three white officers in the case.
Twelve months after the killing - in which police shot Taylor while looking for a former friend of hers - only one of three police officers has been charged.
Brett Hankison, was charged with three counts of wanton endangerment for firing into a neighbor´s apartment.
© Associated Newspapers Ltd.