Chief public prosecutor Noordin Haji has accused Sonko, who was arrested on Friday, and his associates of the misappropriation of 357 million Kenyan shillings ($3.5m).
Sonko pleaded “not guilty” to all the charges when he was arraigned before anti-corruption court magistrate Douglas Ogoti on Monday in a packed court secured by anti-riot police.
“You knowingly acquired property and money knowing it was the proceeds of crime,” a state prosecutor read out one of the charges, to which Sonko replied: “Not true.”
State prosecutors also read out details from Sonko’s bank accounts and several dates on which money was wired in from contractors who had won tenders in the city county.
Sonko was represented in court by a high profile team of Kenyan lawyers including the Senate Majority leader Kipchumba Murkomen.
The governor spent the weekend in jail after his dramatic arrest in southern Voi saw him scuffle with police before being bundled in a helicopter and flown to Nairobi.
He said in a statement on Sunday that his arrest was politically motivated and that he was a law-abiding citizen.
Sonko urged his supporters to avoid any actions that “may threaten the peace”. Police used teargas to disperse hundreds of Sonko’s supporters when he was called into the anti-corruption office for questioning in November.
“What I ask of you, my supporters, is to pray for me. Even all my haters, please pray for me,” the statement, written partly in English and partly in Swahili, read.
Born Gidion Mike Mbuvi, the governor formally adopted the nickname “Sonko” which is Swahili slang for a rich and flamboyant person.
It was seen as a maverick move when, in 2017, the ruling party chose him as its candidate for Nairobi’s gubernatorial poll.
He has previously spent time in jail – for failing to respect court dates – and has denied allegations of illegal activities, including drug trafficking.
He is beloved by poor Kenyans for running his personally branded fire trucks and ambulances to assist people living in the slums.
He is also known for his style mimicking an American rapper, dripping with expensive gold and diamond jewellery, and on occasion, golden shoes. He recently drew criticism for displaying his opulent dining room on social media.
He also has a fleet of gold-coloured cars.
Kenyans and investors have long complained of corruption in Kenya, East Africa’s business hub and the region’s richest economy. President Uhuru Kenyatta has promised to crack down on the problem.