In 1825 he became reader and teacher at the Sephardic community of Semlin, and then its rabbi a few years later. Semlin, today's Zemun district of the Serbian capital Belgrade, was at that time part of the Austrian Empire's Military Frontier. At the time of Alkalai's arrival, the region was experiencing strong nationalist movements, and the Serbian War of Independence, which led to the creation of a new Serbian state after centuries of Ottoman occupation, gave impetus to new nationalistic ideas among Balkan Jews such as Alkalai.