Geagea, anti-Syrian leader of the now-disbanded Christian Lebanese Forces militia, was the only militia chief jailed after the conflict.
Parliament, now dominated by opponents of Damascus, passed a bill granting him amnesty last week, the latest reconciliatory step in civil war-scarred Lebanon after the recent collapse of Syria's military dominance.
"You have come out of the big prison which you had been put in and you have taken me out with the same act from the small prison which I had been put in," said Geagea on Tuesday in his first public address after he was released earlier in the day.
"They were long, dark black years," he said during a nationally televised speech at Beirut's international airport attended by several hundred applauding supporters and journalists.
Geagea, 53, left his Defence Ministry cell in Beirut and soldiers escorted him straight to the airport where he met Lebanese Forces supporters at the VIP lounge.
He is also scheduled to meet several Lebanese officials and ministers.
Absent from those meetings will be those who were not present in the cabinet session on 18 July when a motion was passed to pardon Geagea, Aljazeera's correspondent in Lebanon, Abbas Nasir reported.
"You have come out of the big prison which you had been put in and you have taken me out with the same act from the small prison which I had been put in"
Samir Geagea, jailed former militia chief, after being released
Among those who were not present were the Hizb Allah bloc, some representatives of the Baath Party and the Syrian Socialist Nationalist Party.
Geagea is to leave the country for medical tests and rest.
He had been serving several life sentences for assassinations and other civil war killings and spent eight years in solitary confinement and 11 years in total at a Defence Ministry jail.
Geagea has been linked with some of Lebanon's most notorious civil war-era killings, including the 1987 bombing of a military helicopter that killed the pro-Syrian Prime Minister Rashid Karami and the slaying of Danny Chamoun, a prominent Christian politician.
He was arrested in 1994, and his group was outlawed after a church bombing killed 10 people.
Former rival Michel Aoun returned
from exile in France in May
Later, Geagea was acquitted of the bombing, but sentenced to life terms on several other murder counts, including the killings of Karami and Chamoun.
He has always maintained his innocence, saying he was victimised for his staunch opposition to Syria.
Syrian influence over Lebanese politics had stymied past attempts to secure his pardon and the return of former Lebanese army commander General Michel Aoun from 14 years' exile in France.
But Aoun returned on 7 May, less than two weeks after Syria withdrew its troops under US and UN pressure, sparked by the
14 February assassination of former prime minister Rafiq al-Hariri.
Geagea's amnesty was backed by former Muslim and Christian civil war foes newly united against Syria and emboldened by the end of its 29-year military presence in Lebanon.