Dimas was born in 1971 in Himara, southern Albania, to ethnic Greek parents.

Dimas started the sport at 11 and competed at a junior’s level at 14. At 18, in 1989, he became triple Champion of Albania for the 82.5 kg category and in 1990 he repeated himself.

He was part of the Albanian weightlifting team to which he made important contributions: In 1989 in the 62nd World Championship of Weightlifting Dimas ranked 12th in the World and helped Albania rank 13th in the world.).

While in Albania, he was coached by Zef Kovaci. In 1990 he was also accorded the title “Master of Sports” by the Albanian government and the title “European Master” by the European Weightlifting Federation.

During his stay in Aalborg he came in contact with representatives of the Greek national team: Giannis Sgouros and Christos Iakovou and he expressed great enthusiasm for a future cooperation. However, the political situation in the People’s Republic of Albania prohibited him from leaving the country. Dimas managed to cross the Greek-Albanian border at 7 February 1991, after a several hour exhaustive trip. He then stayed in Athens. He acquired Greek citizenship in 1992, and first competed under the Greek flag in the 1992 Summer Olympics, winning the gold medal in the 82.5 kg class.

With the 1993 and 1995 World titles under his belt, Dimas was the favorite to win Olympic Gold in the 83 kg class at the 1996 Summer Olympics, where he was the flag bearer of the Greek Olympic team. He won the event with two new World Records.

At the 2000 Summer Olympics, he won yet another gold medal, this time in the 85 kg class. This made him one of just three weightlifters at that time to have won three Olympic gold medals, the others being Naim Süleymanoğlu (Turkey, but born in Bulgaria) and Kakhi Kakhiashvili (Greece, but born in Georgia). Halil Mutlu (like Süleymanoğlu, a Bulgaria-born Turk) would become the fourth in 2004.

At the 2004 Summer Olympics in Athens, Greece, Dimas was again chosen as Greek flag bearer for both the opening and closing ceremonies. Dimas was recovering from knee surgery and a hurt wrist and was not expected to compete in these Olympics, but he came away with a bronze medal in the 85 kg class, becoming only the fourth weightlifter in history to win a medal at four different Olympic Games, the third to win those four medals successively, and the only one whose four medals include 3 golds, thus cementing his status as a national hero in Greece and as an international weightlifting legend.

In June 2008, Dimas became vice-president, and in October 2008 president of the Hellenic Weightlifting Federation.

In 2012 Dimas entered politics as a member of PASOK. He was soon polemical with Greece’s policies with Northern Epirus, claiming that the Greek government has “forgotten” it.

On 17 February 2014 Dimas participated in the ceremony of 100th anniversary of the declaration of Autonomy of the Republic of Northern Epirus. Dimas propagates against what he considers to be discrimination policies of the Albanian state against the Greek community of Himara.

Dimas was married to Anastasia Sdougkou, a former Greek National Television (ERT) sports reporter. Together they had four children, Eleni (b. 1995), Victor (b. 1998), Maria (b. 2000), and Nickolas (b. 2009). When he was in his youth, he idolized the former Soviet (Armenian) weightlifter of his senior category, Yurik Vardanian, whose son, Norik Vardanian idolized him when he (Norik) was a child. His wife Anastasia Sdougkou died of brain cancer on 14 June 2018.