In a campaigning speech to the Fabian Society Gordon Brown said Labour would create "more middle-class jobs than ever before".
He said Labour represented the "mainstream majority" and suggested middle-class voters would suffer disproportionately under Tory plans to cut public spending.
He conceded that Labour would have to cut public spending but said the way out of recession was to "unleash a wave of social mobility" not seen for more than six decades.
The Tories said it was "laughable" for Brown to present himself as the saviour of the middle classes.
Shadow chief secretary to the Treasury Philip Hammond said: "Middle Britain won't forget that it was Gordon Brown who destroyed their pensions, increased their taxes and crippled social mobility.
"The idea that a man who has spent his whole career at war with the middle classes can be their champion is laughable."