Alemu went on to become an acknowledged master of the instrument, first recorded in 1972 by Cynthia Tse Kimberlin for a major UNESCO collection, and performing and broadcasting around the world.

In 1974, however, the Derg military junta came to power in Ethiopia; their anti-religious policies also included the banning of the begena from radio broadcasts, and the closing down of the Yared School's teaching of the instrument.

As a result, Alemu Aga decided to give up his teaching post in 1980, and opened a shop in Addis Ababa Piazza district.

For a time he played only in private, but the collapse of the Derg's régime led eventually to a change in state policy, and Alemu again began to teach and perform in public.

In 2009, he released the CD "The Begenna of Elders – The Harp of David in Ethiopia" as well featuring the begena music of Seyoum Mengistu, Admassu Fikre and Tafesse Tesfaye.