Born in Elbasan and completed his formal education in Rome, where he obtained a degree in Physics. Upon returning to his home country, he worked as a teacher in a high school in Shkoder. In April 1939 he took part in an anti-Italian demonstration in Shkodër. After the Italian invasion he lost his job and returned to Elbasan.
At the end of 1941, he established contacts with a nationalist organization and created his own armed unit operating in the Bradashesh- Labinot-Peqin area where he collaborated with the units of Hamit Matjani and Isa Manastirliu.
In September 1943, he organized an ambush on a German unit leaving Elbasan. After the formation of the pro-German cabinet in November 1943, Lleshanaku was appointed Commander of the Gendarmerie in Elbasan with the rank of major.
After the communists came to power in November 1944, he joined Kapidan Mark Gjon Marku and Halil Alina in their fight against the communist troops. On December 16, 1946 he left the territory of Albania and escaped to Greece. He reached Athens in January 1947 and began working with the Albanian refugee community in Piraeus.
In February 1949 he was part of Plan I of the mission drop into Albania, sponsored by the BKI with Italian assistance and parachuted with a group of four, who were tasked with gathering information about the situation in Albania and the reorganization of the nationalist troops in the northern part of the country.
Lleshanaku, together with Xhevdet Blloshmi, moved from northern Albania to Elbasan, where nationalist troops were still active. From there, he sent reports to Rome, where L’Albanie Libre Gazette, an active organ of the BKI, was active.
From the beginning of his mission in Albania, Lleshanaku was sought by the Sigurimi and his group had several infiltrators. On December 24, 1950 Alush Lleshanaku was killed in a house in Elbasan. To destroy any evidence the sigurmi burned the house.
Lleshanaku’s body was exposed for public view for several days, and then buried in an unknown grave. People who helped Lleshanak during his stay in Elbasan were brought to court and three of them were sentenced to death