[4] He graduated from Saint Mary's University in 1996 with a Bachelor of Commerce in Finance and is a Chartered Professional Accountant.

[8] On April 1, 2014, he was appointed Minister of Internal Services, a new department including the responsibilities of the former Information Management portfolio, as well as various other support functions within government.

[11] On June 15, 2017, premier Stephen McNeil shuffled his cabinet, moving Kousoulis to Minister of Labour and Advanced Education.

[12][13] Kousoulis has been a member of the Treasury and Policy Board since his appointment to the Executive Council of Nova Scotia in 2013.

On September 30, 2020, Kousoulis announced his candidacy for the Leader of the Liberal Party of Nova Scotia and to become the 29th Premier of the Province.