Sylejman served as Imam in the Bajrakli Mosque, owner of land, stores and mills in Prizren area.

After the studies he worked in the madrasa of Prizren, where he distinguished himself as a main supporter of the lower classes against the injustices of the corrupt 19th-century Ottoman administration.

Once the Russo-Turkish War started off in (1877–1878), he set up together with other Albanian leaders, to work for the protection of Albania's territorial integrity and to seek its national rights in international level.

In the spring of 1878, he chaired the committee that organised in Prizren General Assembly meeting, who founded the Albanian League.

As its chairman, he directed political activity that led to the establishment of the Vilayet of Albania, administration and organisation of armed resistance against the Ottoman armies which were coming to crush it in the spring of 1881.