The president said Mr Roble was selected on the basis of “his knowledge, experience and ability to move forward with state-building efforts and the development of national plans”.
If Mr Roble wins the confidence of parliament, he will replace Hassan Ali Khaire, who was ousted in a no-confidence vote by parliament on 25 July.
President Farmajo, in a statement, urged the prime minister-designate to “immediately form a capable government that will lead the country to elections and make significant efforts to consolidate security gains, rebuild the armed forces, develop infrastructure, expand basic services”.
Mr Roble is a relative newcomer to Somali’s politics.
His predecessor fell out with President Farmajo over differing views on the election due early next year. Mr Khaire had insisted that “elections should be held on time… to avoid a political, security and constitutional crisis”.