He attended an Italian elementary school and later the Xavierian Shkodër Jesuit College before studying from 1904 to 1908 in Klagenfurt, southern Austria in order to become a teacher.

In 1911, he took part in the Albanian uprising of northern Albania against Montenegro and the Ottoman Empire.

[1] In 1924, Mosi was one of the main supporters of the revolution that overthrew the regime of Ahmet Zogu and established a democratic government.

Fan S. Noli became the new Prime Minister, while Mosi served as a prefect of Korçë and Gjirokastër.

After the restoration of Zog's regime he was initially exiled but returned to Albania in 1927 after amnesty was proclaimed and served anew in the government as minister of public works.