People staged the rally in Birmingham city centre's Centenary Square as plans for a similar event were announced in Wolverhampton for Sunday.
Mr Floyd died after a white officer held him down by pressing a knee into his neck in Minneapolis on May 25, sparking days of protest in the US.
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Birmingham City Council urged demonstrators to keep two metres apart ahead of the Black Lives Matter demonstration in the city centre.
Thousands of people attended the rally from 4pm, with Aston Villa defender Tyrone Mings, showing his support by telling his 109,000 Twitter followers: "Don't be afraid to speak your truth. Stand for what's right."
Some estimates put the gathering at around 2,000 people while others said there were up to 5,000 at the rally and subsequent parade.
It comes after pockets of protesters clashed with police as thousands of people flooded into central London and abandoned social distancing for a BLM demonstration on Wednesday in response to the death of George Floyd in the US.
West Midlands Police said "we recognise there will be lots of emotions by many people who feel moved by what they saw and want to express their frustrations".
Assistant Chief Constable Matt Ward said: "Our aim is to allow and facilitate peaceful protest, and therefore we are not going to stop people coming out on to the streets if they've got legitimate concerns they want to share.
"You can still protest while maintaining social distancing."
West Midlands Mayor Andy Street said: "To those protesting peacefully in Birmingham today, please keep a two-metre distance at all times and do all you can to protect yourself and others from the spread of Coronavirus.
To those protesting peacefully in Birmingham today, please keep a two-metre distance at all times and do all you can to protect yourself and others from the spread of Coronavirus.— Andy Street (@andy4wm) June 4, 2020
The West Midlands stands behind you, but we cannot forget about the deadly threat of Covid-19.
"The West Midlands stands behind you, but we cannot forget about the deadly threat of Covid-19."
Birmingham City Council said it supports the BLM movement but urged protesters to keep two metres apart and stay in groups of six or fewer.
The protest moved from Centenary Square after 6pm with a march through Victoria Square where hundreds took to one knee in a show of solidarity in a gathering outside Birmingham City Council House.
Others marched onto West Midlands Police's headquarters Lloyd House where there were chants and speeches through a loudhailer.
People also marched through the Dale End area of the city as gathering slowly dispersed after 7pm.
After a largely peaceful demonstration in Hyde Park in London on Wednesday, during which Star Wars actor John Boyega gave an impassioned speech, tensions later escalated outside Downing Street with 13 arrests including after the assault of Australia TV reporter Sophie Walsh
Prime Minister Boris Johnson said he was "appalled and sickened" to see what happened to Mr Floyd, while chief constables from across the UK issued a joint statement saying they "stand alongside all those across the globe who are appalled and horrified".
A protest to support the Black Lives Matter movement will be held in Wolverhampton's West Park on Sunday.
Organiser Shereen Walker has said the protest will take place at 2pm to coincide with the protest due to happen in London outside the US embassy.
The 300 names of the victims of police brutality in America will be read out during the West Park protest, supporters will take a knee for a moment of silence and then close in prayer for the protesters, victims families, and the community.
Messages showing support for the Black Lives Matter movement have been posted onto electronic signs in Wolverhampton.
It comes as Wolverhampton-born singer Beverley Knight recorded an emotional video opening up about her experiences of racism.
Beverley, 47, also said racism and black people being treated differently was not just an issue solely confined to America.
She said in the video posted on Facebook: "Black lives matter. It's not saying only black lives matter. It's not saying black lives matter to the exclusion of every other life, of course not.
"When people reply to black lives matter on social media with 'yeah, well all lives matter', I often think to myself I wish all lives did matter.
"Quite obviously, as is evidenced right now in the US, quite visibly, we can see that some lives matter way, way, way less than everybody else's. And that is - let's be completely real here - the lives of black people."