Michalis was a Fellow member of the Institute of Chartered Accountants in England and Wales and a member of the Institute of Certified Public Accountants Cyprus.

In 1996, Michalis founded the Polydorides & Associates Consultants Ltd. He served Polydorides & Associates Consultants Ltd from the position of Managing Director to January 2020.

In July 2013, Michalis was appointed to the Board of Directors of the Central Bank of Cyprus, where he served for a period of five years to July 2018.

He also served as a member of the Executive Committee of the Cyprus Chamber of Commerce and Industry from 1993 to 2002.

Between 1993 and 1999, he was President of the Limassol Chamber of Commerce .

During the period 1987 and 1996, he was Managing Director of KEO Plc, Cyprus’ largest drinking and beverages group.

Between 1970 and 1987, Michalis was a Senior Partner of the audit firm Scottis & Polydorides and then Managing Partner of Peat Marwick Mitchell & Co which then became part of KPMG International.

He served on the Board of many public and private companies as well as in committees of various cultural and service organisations