During the ceremony, Justice David Baragwanath welcomed Mr Rickards to practise as a barrister and solicitor.
He said Mr Rickards was planning to work with disadvantaged people on treaty matters and employment issues.
Mr Rickards left his job as assistant commissioner in November last year, ending an internal police disciplinary action against him.
In 2006 he and two former police officers Bob Schollum and Brad Shipton were acquitted of historic charges of raping Rotorua woman Louise Nicholas during the 1980s.