 As chief American intelligence officer during the Greek Civil War, Karamessines was instrumental in organizing the Greek Central Intelligence Agency (KYP) along American lines.Karamessines worked undercover in Greece until 1953, and was Chief of Station in Rome from 1959-63 before being appointed Assistant Deputy Director for Plans under Richard Helms, holding the same post under Desmond FitzGerald.When the latter died of a heart attack in July 1967, Karamessines succeeded him as Director for Plans (with Cord Meyer serving as the Deputy Director for Plans).