A distinguished officer, he is also notable for his participation in resistance groups against the Greek military junta of 1967–1974, being repeatedly imprisoned and exiled as a consequence.

Born in Athens on 21 May 1932, Leonidas Vasilikopoulos entered the Hellenic Navy Academy on 7 October 1949 and graduated on 18 June 1954 as a Line Ensign.

[1] The reason for his early retirement was his persistence in marrying Nota Iliopoulou, daughter of Stavros Iliopoulos, an MP of the United Democratic Left, successor of the banned Communist Party.

He was re-arrested on 21 May 1973 for his participation in the Antidictatorial Youth-EAN group, and condemned to two and a half years in prison, but released in the general amnesty of 21 August.

[1] Promoted to vice admiral on 20 January 1986, he assumed the Fleet Command, before being appointed Chief of the Navy General Staff on 22 December 1986.

[1][3] In October 1993, he was appointed as head of the National Intelligence Service by Prime Minister Andreas Papandreou, a post he held until dismissed following the Imia crisis with Turkey in early 1996.

[3] During the latter crisis, the Greek government's handling of the situation was hampered by the intense distrust shown by the newly appointed Prime Minister, Kostas Simitis, towards the incumbent military and intelligence chiefs, Vasilikopoulos among them.