Osseiran played a significant role at various points in the history of modern Lebanon, such as the struggle for independence (1943), the mini-civil war of 1958, and the Lausanne Conference for Peace (1984).

The Osseiran family traces its Shia origins to what is now Iraq and there to the tribe of the Bani Asad, which fought alongside Husayn ibn Ali at Karbala in 680.

After their defeat the survivors suffered persecution and after an unknown period of time one of the tribal members - Haidar - reportedly fled to Baalbek, where he had two sons: Ali and Osseiran.

[1] Historians have established that the Osseirans rose to prominence and power as grain merchants in Sidon and the Jabal Amel region of modern-day Southern Lebanon soon after the Ottoman Empire assumed control over the area in 1516:"Having arrived some time in the sixteenth or seventeenth century and built up significant wealth from mercantile activities, they were eventually appointed consuls for Iran.

This allowed them to build their wealth more rapidly and to gather a greater supporter base in Saida and Zahrani (where they owned land) due to the privileges accorded their employees.

[citation needed] In 1936 he married Souad Al Hajj Ismail Al-Khalil, by whom he had seven children: Abdullah, Ali, and five daughters: Zhour, Afaf, Samia, Zeina, and Leila.

However, he rejected all manner of legal counsel and undertook his own defense, turning it into a vigorous and spirited attack on the wrongdoings of the French mandatory authorities, as he saw them.

In 1943 the new President Bechara El Khoury, PM Riad Al Solh, along with the rest of the cabinet of which Osseiran was a member, proceeded to abolish the articles of the constitution that tied Lebanon to the French Mandate.

[6] During the mini-Civil War of 1958 he played a significant role in ending the riots and disturbances and securing the election of General Fouad Chehab as President of the Republic.