It means Mr Drummond, already one of the longest serving managing partners in the UK, will stay on for a further three years having held the top post since 1998.
Under his tenure the firm has grown from 175 staff at its office in Edinburgh to more than 530 including 77 partners and 333 lawyers and other fee earners.
As well as premises in the capital it now operates from Glasgow, Aberdeen and is the only Scottish law firm with a site in Brussels.
During the same period turnover has increased from £8 million to £42.8m with profits going from £2.5m to £17.6m.
Mr Drummond is also a long serving board member and current deputy chairman of the Scottish Council for Development and Industry.
Joyce Cullen, chairwoman of Brodies, said: "Bill's re-election demonstrates that our partners continue to put their faith in his ability to build on our success by moving Brodies forward.
"Bill may be one of the UK's longest-serving managing partners, but his passion for the job and his determination constantly to improve the service we offer our clients – long-standing and new – are undiminished.
"Under his leadership, Brodies has been able to achieve, and in some cases surpass, a series of ambitious growth and quality targets and has brought together for the benefit of clients a team of talented lawyers, whose knowledge and expertise is, I believe, unparalleled in and completely relevant to Scotland in 2012.
"Bill is not somebody who rests on his laurels and he has led from the front to inspire new recruits and lawyers at all stages of their career.
"He is passionate not only about the success of Brodies but also of our clients and the wider Scottish economy, which he has demonstrated through his ambassadorial role for the firm and enthusiastic involvement with the SCDI to promote inward investment and international commerce and through Brodies' creation of hundreds of valuable Scottish jobs."
Last week, Brodies appointed construction specialist Alistair McLean as a partner in Edinburgh and litigator Ken MacDonald as a partner in Aberdeen.
Separately Shepherd and Wedderburn has announced the appointment of two partners from Pinsent Masons.
Clare Foster joins the corporate team in Edinburgh while planning and environmental specialist Scott McCallum will work out of the Glasgow office.