Sotirios grew up in the village of  Έλος (Elos) in Laconia, Greece. In his family, there were ten children, three girls and seven boys, with Sotirios being the seventh child. He was one of only two boys in his family to attend high school. Sotirios arrived in Australia in June 1955 when he was 21 years old. Sotirios made significant contributions to the community through his real estate company, established in 1967, just 400 meters from the Pallaconian Brotherhood House. Naming his company Sam Mihelakos and Co., located at 477 Sydney Road, Brunswick, he became a renowned Greek real estate agent, with a dedicated Greek staff. Even after formally retiring at the age of 85, he continued to assist the local Greek community, demonstrating responsibility, respect, prudence, and trustworthiness.

Sotirios regularly helped people he knew within the local Greek and broader Australian communities and dedicated a significant amount of time Greek community organisations in Melbourne.  He became an active member of the Association of Epidaurus Limera of Laconia, covering the eastern region of the prefecture, including key cities such as Molaioi and Monemvasia. Through its activities, this association successfully established a robust collective fund, greatly contributing to the revival of traditional gatherings of Laconians in Melbourne. With the combined efforts of the Association of Epidaurus Limera and other local associations, unity among all Laconians in Melbourne was achieved. These actions played a pivotal role in the establishment of the Pallaconian Brotherhood ‘ O LEONIDAS’, formed in 1961.

Sotirios invested significant time and effort into the club, serving as its president from 1988 to 1990, and again from 1994 to 1995. Throughout his lifelong involvement, he held various positions on the executive committee, including secretary. A proud Spartan, he tirelessly worked to foster community connections.