In 1956, he was one of the authors of Manifeste de la Conscience Africaine, which demanded the right of Africans to self-rule. In 1958, he was one of the founders of the Mouvement National Congolais. When the movement split a year later, he joined the camp led by Albert Kalonji.[2]
After independence
Iléo was voted into the Senate and then voted its president. On 5 September 1960, he was declared prime minister by the president, Joseph Kasavubu. He held the post until 20 September 1960.[3] Under his successor, Albert Ndele, he served as Minister of Information. He was again declared prime minister on 9 February 1961. He remained in this post until 2 August 1961.
In April 1990, he founded the PDSC, and was chairman of it until his death in 1994.