Mayor of Thermaikos is Georgios Tsamaslis. He was born in 1960 in Mesimeri, Thessaloniki. He is the father of two children.

In 1994, he was elected Prefectural Councilor of Thessaloniki in the first elected administration of the Prefecture. In 1998 he was re-elected at this position. In 2002, he was re-elected for the third consecutive time as Prefectural Councilor in the Prefecture of Thessaloniki, assuming the position of Deputy Mayor for Development and Trade.

In 2006, in the last Prefectural elections, Tsamaslis was re-elected for the fourth consecutive time in the Prefecture of Thessaloniki, this time taking the position of Deputy Mayor for Development and Rural Economy, as well as the Deputy Mayor for Tourism, while at the same time assuming the position of coordinator of the Prefectural projects.

In 2010, in the first Regional elections with the Kallikratis system, Tsamaslis was elected a second Regional Councilor of Central Macedonia.

In 2013 he was elected Deputy Regional Head of the Metropolitan Unit of Thessaloniki with Apostolos Tzitzikostas as Regional Governor. At the same time, he was elected president of the Tourism Organization of Thessaloniki, where he remains until 2015.

In 2014 he became the leader of the Thermagikos coalition in the Municipal elections winning 35% of the vote, making it the largest opposition party. In 2019 Georgios Tsamaslis was elected mayor of Thermaikos.