Coexistence at risk
Jumblatt said "things [had] deteriorated in the area af Aley in such a way that is threatening the coexistence with our Shia brothers".
"I agreed with [Nabih] Berri [the parliamentary speaker] to entrust Talal Arslan with seeking to put an end to all the fighting," he said.
"I say to my supporters that civil peace, coexistence and ending the destruction [must] prevail over all the other considerations."
Jumblatt's statement came as the number of dead and wounded continued to rise.
"From the day the unrest started, 42 people have been killed and 164 wounded across the country," a Lebanese security official said.
Arab League foreign ministers meanwhile held emergency talks in Cairo on the Lebanon crisis - in the absence of Syria's foreign minister.
Governments led by Egypt put forward a draft resolution implicitly condemning Hezbollah for the violence but it elicited opposition from some delegations, delegates said.
In Beirut, Fouad Siniora, the Lebanese prime minister, and some of his ministers and staff observed a moment of silence at the government building in honour of those killed in violence.
Opposition fighters seized much of the city on Friday after battles with government supporters.
But Beirut is now coming under the control of the army after opposition forces were ordered to stand down by their commanders.
However, the opposition says it reserves the right to lead a campaign of civil disobedience until its political demands are met.
Al Jazeera's Rula Amin, reporting from Beirut, said Sunday's fighting can be considered "round two" of the conflict.
"This is a significant move. Walid Jumblatt was, through history, a prominent leader in the mountainous areas of Lebanon," Amin said.
"He fought in the civil war and his fighters have a reputation for their viciousness.
"Now he is asking the opposition to quell the violence, as they seem to be in control of the area."Tripoli battles
Earlier on Sunday the army moved into the main northern city of Tripoli, where fierce clashes left one woman dead and at least five people wounded overnight.
The fighting, which continued throughout the night, came hours after Lebanese opposition forces started to withdraw from the streets of Beirut.
An Al Jazeera correspondent reported on Sunday that all groups involved in the Tripoli clashes had agreed on a truce to allow the evacuation of injured people.
An army officer said government supporters fought loyalists of an Alawite sect with links to Hezbollah in the Bab al-Tebbaneh, Kobel and Jabal Mohsen neighbourhoods.