His uncle Tamer (1856–1914), a judge during the Ottoman era, was a well-known poet who stood publicly against the arbitrariness and corruption of Wasa Basha (Arabic واصا باشا), the plenipotentiary governor of Mount Lebanon.

His father, Shibli (1875–1961), was celebrated as the "Poet of the Cedars" (Arabic شاعر الأرز) in Cairo and Alexandria, Baghdad, Damascus, Aleppo and Haifa, and entertained close friendships across the region, from then Emir Abdallah of Transjordan (later King Abdullah I of Jordan) to the first president of independent Lebanon, Bechara El-Khoury.

[2] Wajdi Mallat was educated at the Jesuit college of Beirut, then studied for an advanced degree in Latin while earning a Masters in law from Saint Joseph University,[3] where his classmates included many of the subsequent intellectual and political leaders of Lebanon.

Wajdi Mallat was attached early on to the unique interwar experiment of liberalism in the Levant, especially Egypt, which he lived first hand from the close friendship between his father and the leader of the Egyptian national movement, Saad Zaghloul.

[4] As the young representative of the Lebanese delegation to UNESCO, which held an early Congress in Beirut in 1948, he made friends with intellectuals including Taha Hussein and Louis Massignon on his trip to Paris in preparation of the meeting.

As a lawyer, he defended celebrated cases in Lebanese modern advocacy, winning landmark judicial victories on behalf of the Vatican and the Beirut Maronite Church.

In 1964, he was appointed Minister of Social Affairs by Lebanese president Charles Helou, but resigned a year later over the arbitrary dismissal of leading judges under the pretext of fighting corruption.