A senior aide to Jumblatt said the meeting on Thursday was a positive development that will help defuse political and sectarian tensions.
"I hope it will be the beginning of an open dialogue among all the Lebanese because Lebanon's problems cannot be solved except through dialogue," Ghazi Aridi, Lebanon's public works minister, said.
"With this meeting, there will definitely be a positive atmosphere in the country."
Hezbollah's Al-Manar television aired footage of the meeting, but did not say where it had taken place.
Nasrallah has been in hiding since the 2006 Israel-Hezbollah war because of fears he could be assassinated by Israeli agents.
The channel reported that the two leaders planned further talks.
In the past, Hezbollah has insisted on veto rights in cabinet to guarantee it can block any attempt to get rid of its weapons, but Jumblatt has said he does not support such a move.
The new parliament is expected to meet next week to elect a speaker and then to choose a prime minister-designate, who must be a Sunni Muslim in Lebanon's sectarian power-sharing system.
Saad Hariri, the Sunni leader of the March 14 coalition, has expressed interest in becoming the next prime minister in a national unity government.
Also on Thursday, Mohammad Raad, Hezbollah's parliamentary leader, held talks with Frances Guy, the British ambassador to Lebanon, in the first such contact between the group's political wing and a senior British official.
"The talks covered the recent election and the situation in the region," Hezbollah said in a statement.
British officials confirmed the meeting and said that they were open to further talks.
A foreign office spokeswoman in London said Britain would make a "distinction between those members of Hezbollah who are legitimately involved in Lebanese politics and those who are involved in violence and support terrorism.
"We will be taking a pragmatic approach to speaking to known moderates, political figures who to the best of our knowledge have no links with acts of violence."
Britain, which designates the military wing of Hezbollah as a "terrorist" group, said it was prepared to engage in direct contacts with the political wing after it joined a national unity government last year.