His father, Dr. Abdul Rahman El Ounsi, was a prominent general practitioner, had been one of the first Beirut Muslims to study modern Western medicine[1] and his mother came from the prominent Sunni Muslim family Salam, who notably dressed in Western attire.
[5] In around 1922, he travelled to Amman, where he settled for a number of years (1922–1927),[6] and taught painting and English to the children of King Abdullah.
[11] A Lebanese woman, known simply as Grandma Kamal, visited Onsi at his Tallet Al-Khayat property in the late 1930s, and recalled that there were many gazelles roaming about.
At that time, the market for Western-influenced art was emerging as the educated middle-classes and elites began to purchase works by local artists.
[9] Along with artists, Mustafa Farrukh (1901–1957), César Gemayel (Qaisarr Jumayil) (1898–1958), Saliba Douaihy (Saliba Duwaihi) (born 1915) and Rachid Wehbi (Rachid Wahbah) (born 1917), Osni is regarded as a pioneer, having laid the foundations for a modern arts movement in Lebanon.
[16] Osni focussed on natural views (al-manazir al tabi'iyya) in which he strove to remove "traces of himself as a rationalizing being and to react unselfconsciously with sure draughtsmanship, direct brushwork, and heightened sensitivity to optical effects."