Minna Nathoo, who was executive director for diversity and talent, had 'reached a compromise agreement', a council spokesman said.
She criticised Ealing in remarks in a local newspaper, saying it was cutting services while spending on 'glitzy bits'.
Housing and social services director Norman Tutt went in October.
'We know there is a lot of discontent among some of our best officers, and other top resignations may follow.'
Ealing is implementing a customer engagement programme called Response, which involves a radical reorganisation of the council.
Mr Gibb added: 'We are seeing chaos in the senior management team of the council, and it seems that if senior management do not agree with the Response programme they are forced to leave.'
Chief executive Gillian Guy said: 'We are not expecting any more departures.
'Ealing Council does not dismiss employees who raise concerns. On the contrary we welcome constructive criticism.
'But if we are to make progress towards delivering the ambitious customer service targets Ealing has set for itself, we must have everyone on the team working towards the same goals.'
Ms Guy said the departure in quick succession of two senior staff was 'not uncommon in large organisations, especially in the middle of such fundamental change. It may not be ideal, but we have to accept it and move on'.
The Conservatives claimed Response would cost £35m over three years. But a council spokesman said £4.85m was allocated for this year and future spending had not yet been agreed.