Kostas Gerolymatos was born, raised and lives in Halandri with his wife and two children. He is a mining-engineer and has worked as a construction engineer and safety officer in big infrastructure projects.
He has been a member and president of the Board of the Mining Engineers Students‘ Association of NTUA and the corresponding graduate association, member of the Construction workers’ union (metro branch), representative of the Parents‘ Association of the 4th primary school of Halandri, and president (and of the founders) of the Chalandri Parents’ Cooperative (School). Besides that he has participated in many local citizens’ initiatives and campaigns throughout his political life.
He was elected in the city council first in 2014 and since then he has served from the positions of Deputy-Mayor of the Technical Department (2014 – 2019) and Deputy-Mayor of Programming, Development and Digital Governance, as well as of Waste Management (2019 – today).