Educated first at Nabeul, then at Sadiki College, Tunis, and finally in France where he graduated from the Polytechnic in Paris as an engineer.
In 1959 he joined the Public Works Department at Le Kef, 100 miles south-west of Tunis, and was quickly promoted to Deputy Chief Engineer on bridges and highways. In 1961 he was made Transport Director; then a year later Head of Shipping and Civil Aviation. In August 1965 he was appointed Director-General of the State Railways.
He moved to the Department of Planning and National Economy in September 1967 as Director of Industry. In January 1969 he was appointed Director-General of ICM the Maghreb Chemical Industries. He entered the cabinet on November 7, 1969, as Minister of Public Works. President Bourguiba promoted him a year later to Minister of National Economy, where he remained after the government reshuffle on October 29, 1971. Chelli was replaced on March 22, 1972, by Chedli Ayari.
Technocrat-politician, an expert on bridges whose training as an engineer and experience in public works have given him a commanding authority in handling the country’s industrial development. Earnest and efficient, he is trusted to get on with any job assigned to him without being concerned with jockeying for political advantage. Although a late-comer to politics, he plays an important role on the economic front.