[8] Melissanidis is in the top ten rich list of Greek entrepreneurs ranking in 6th place.
He is the founder and former owner[10] of Aegean Marine Petroleum Network Inc. which is the second strongest and largest independent fuel supplier in the world.
On June 7, 2013, with AEK relegated to the Amateur Division because of financial problems, Melissanidis became again active for the club as an administrator.
[18] The investigation found that a set of shell companies, fake receipts and documents covered up the misappropriation making it look like Aegean had legitimate contracts with customers that would explain the missing cash.
[19][20] AMPNI filed for Chapter 11 bankruptcy and was acquisitioned by the Mercuria group,[21] and operates as Minerva Bunkering.
In the summer of 1992, Melissanidis alongside his business partner, Ioannis Karras bought the shares of Andreas Zafiropoulos and became the major shareholders of AEK Athens F.C.,[33] with the former becoming the president in 1992–93 and 1994–95 season.
During their ownership the club faced great success, winning 2 championships in a row and became the first Greek team to ever compete in the group stage of the UEFA Champions League.
[35] On 7 June 2013, Melissanidis became again active for AEK, after they declared bankruptcy, in order to save the club and bring them back to success.
[40][41] On 2 October 2013, the board of AEK Athens, under Dimitris Melissanidis, presented plans for the new stadium to the municipality of Nea Filadelfeia, in order to gain permission to build.
[47] Dimitris Melissanidis is a major shareholder in OPAP and is the largest investor, investing €157 million in the takeover.
[49] On 18 February 2022 it was announced that the Melissanidis family had sold its entire stake in OPAP to Allwyn, owned by Czech billionaire Karel Komarek, for a price of EUR 327.4 million.
[50] This development is not unrelated to the lawsuits that Mr. Dimitris Melissanidis, his son George Melissanidis and their companies are facing in connection with Aegean Marine Petroleum Network, especially since Allwyn has announced its plans to publicly list on the New York Stock Exchange (NYSE), working in partnership with special purpose acquisition company Cohn Robbins Holdings Corp.
[51][52] Melissanidis has social and philanthropic action, mainly in cooperation with the Church of Greece and the Ecumenical Patriarchate of Constantinople.
You dare to sign [the Intralot and lottery contracts] and I will take your head off”, Louropoulos quoted Melissanidis as telling him on May 20, 2013”, according to the "Financial Times".
[57] Also, immediately after the signing of the OPAP deal, the Greek privatization agency chairman, Stelios Stavridis, was dismissed by Greek Finance Minister, Yannis Stournaras, “for ethical reasons”, when news reports emerged that he travelled on Dimitris Melissanidis’ private jet.
[58] Furthermore, in a highly publicized incident, discussed in the Greek Parliament, calling from an ‘Aegean Oil’ listed telephone number, Melissanidis personally bullied with death threats to Lefteris Charalambopoulos,[59] the Greek reporter (who also related with Evangelos Marinakis [60] rival businessman with Melissanidis) who published the government report in the left-wing ‘Unfollow’ magazine.