In 1955, he enlisted in the French Army and was posted to Algeria during the war of independence in 1957. After his service in the French Army, Conté returned to Guinea, which became independent from France on 2 October 1958, and was integrated into the new army with the rank of sergeant. In 1962, he attended the Camp Alpha officer's school in Conakry. Soon after, he was transferred to the 2nd Battalion artillery-training center in Kindia. On 1 July 1963, he was promoted to Second Lieutenant. This was followed two years later by another promotion from Second Lieutenant to Lieutenant. On 22 November 1970, Portuguese military together with Guinean dissidents invaded the country from Portuguese Guinea (now Guinea-Bissau) in an apparent attempt to overthrow the government of President Ahmed Sékou Touré and destroy PAIGC guerillas. For his service to the nation, he was promoted to the rank of Captain on 27 February 1971. In 1973, he was named commander of the Boké operational zone (in Northwestern Guinea) to assist the pro-independence guerrilla movement, African Party for the Independence of Guinea and Cape Verde (PAIGC) in neighboring Portuguese Guinea. On 10 May 1975, he was named assistant Chief of Staff of the army.