In 1925, the French High Commissioner Maurice Sarrail asked Hasani to form a government during the climax of a national uprising in the Arab Mountain.

The opposition, headed by the National Bloc, accused him of tampering with the ballots to secure his election through Interior Minister Sa'id Mahasin.

Hasani protested to government authorities in Paris, who compensated him with the post of Prime Minister in the administration of President Muhammad Ali al-Abid.

The National Bloc, Hasani's prime opponent in local politics, staged a countrywide strike that lasted for sixty days, demanding that France address the issue of Syrian independence in a serious manner.

During the strike, commercial life was brought to a standstill and hundreds of Syrians were arrested and deported to remote prisons on the Syrian-Turkish border.

The ex-Prime Minister remained on the margins of political life until 1941, when following the Bloc downfall, General Charles de Gaulle appointed him President of Syria on 12 September 1941, after having failed to prevail upon Hashim al-Atasi to return to office.

De Gaulle rewarded Hasani's services by officially recognizing Syria's independence on 27 September 1941 and promising complete French evacuation once the war in Europe ended.

His son-in-law Munir al-Ajlani claims that in his final years, Taj al-Din al-Hasani wanted to distance himself from the French and project the image of a true nationalist, but died before that was done.