Menelik Cowan, who worked for Lambeth Council and lived in Enfield, was convicted of five charges of fraud by abuse of position after trial.
He admitted one charge of fraud by abuse of position and one of possession of false identity documents with intent. The value of his offending was £286,918.92.
Alexander Williams, from Brixton, was convicted of fraud by abuse of position worth £240,345, while working for Barking and Dagenham Council.
Rahel Asfaha, from Poplar, east London, was convicted of eight offences of fraud by abuse of position, worth £181,872. She worked for Lambeth Council and Barking and Dagenham Council.
Hugh Small, from Fulham, who worked for Kingston Council, admitted money laundering but was convicted of a further offence of fraud by abuse of position after trial. The value of his offending is £112,983.
Natasha Francis, from Walworth, who worked for Lambeth Council, admitted a money laundering offence was convicted of being concerned in a money laundering arrangement worth £2,868.
Cassandra Johnson, from Brixton, was convicted of three offences of fraud by abuse of position worth £106,834 while working for Lambeth Council.
Jessica Bartley, from Stockwell, who worked for Lambeth Council, was convicted of one offence of fraud by abuse of position worth £71,600.
Donna Francis, 57, from Brixton, was convicted of money laundering worth £8,323.43 and Derrick Williams, 58, also from Brixton, was convicted of money laundering worth £14,168.03.
Money was sent into accounts controlled by money launderers Bashiru Tahiru and Elaine Agyemang, who left the country before they could be charged.