John Hogan was also charged with the attempted murder of his baby daughter, who survived the four-story fall. A Greek court remanded him for treatment while officials in Greece and England work out plans for long-term care, Sky News reported.
Paraskeri Kiraleou, the senior judge at the trial, said Hogan's "responsibility was diminished."
Hogan, his then-wife, Natasha, and their two children, Liam, 6, and Mia, now 2, had gone to Crete in an attempt to revive their marriage. Hogan jumped from the balcony with his children after his wife told him she planned to leave early and to end the marriage.
"This result, albeit somewhat unexpected, has left me feeling that Liam lost his young life for nothing," Natasha Hogan said in a statement after the verdict.
Hogan, during his trial testimony, called himself a "beautiful father." He said he did not feel guilty because "the person you see before you is not the person who jumped from the fourth floor."