The 43-year-old is the son of former interior minister Michel al-Murr. His aunt, Mirna al-Murr, heads the authority that approves all building licences.
A Greek Orthodox Christian, al-Murr, who is also a lawyer and businessman, is married to the daughter of President Emile Lahoud. They have three children.
Al-Murr held the post of interior minister in the cabinet of former premier Rafiq al-Hariri. Al-Hariri was assassinated in an attack on his convoy in February.
Although regarded as pro-Syrian, al-Murr's father has forged a political alliance with Michel Aoun, a Christian former general who returned in May after 14 years of forced exile for leading a revolt against the Syrian military presence.
Aoun and his supporters won 21 seats in Lebanon's recent parliamentary election, the first since the Syrian pullout.