It means the party has won control of three councils in the capital, along with Waltham Forest and Hackney in north-east London.
In Lewisham – where Labour have been the largest party since 1968 – the Greens toppled a huge majority, winning 40 seats to gain control of the council.
The last time the council was up for election in 2022, Labour won every single seat.
In Lambeth, the Greens gained 27 seats, pushing Labour out of power in the borough for the first time since 2006.
In results on Friday, the party also made big gains in Hackney and Islington, where Labour held on to power despite a Green surge.