The restructure was to ensure that employees were able to deliver "exceptional rather than expected" results and to improve productivity.
And he said it would reduce the bureaucracy and require staff to be more accountable.
"As an organisation we need to work smarter and become more flexible to the needs of our community."
While congratulating the successful candidates, Mr Fell acknowledged the senior managers who have lost their jobs - "I thank them for their contribution to our district."
Two positions are still to be filled - one is general manager people and culture, while council will shortly advertise the role of kaiwhakahaere (cultural adviser), a job already budgeted within the annual plan.
Titles have changed for two other senior managers. Charlotte Almond (group manager of strategy and development) will become general manager of strategy and Mark Hughes (group manager of infrastructure) will become general manager infrastructure.
In an earlier interview Mr Fell said although there were aspects of officers' performance which were progressing positively "there is also a widespread expectation from councillors, ratepayers and residents that we need to improve our performance".
Some management structures were now unnecessary given the way the council did business "and they create barriers for getting things done".
"The bottom line is we've got to make change to a structure that is far too complex for what's required for a district of this size.
"It's about thinking and acting smarter, and being less of a burden on the ratepayers."