[3] Leading one of three coordinated Ottoman armies, Shahin secured key strategic positions to prevent attacks from Serbian and Bulgarian forces, ensuring the success of Murad I's main offensive against the city.

Shahin played a key role in the Battle of Maritsa (or Chernomen) in 1371,[5] where Ottoman forces, under his command, alongside Evrenos Bey, secured a decisive victory over a Serbian-led coalition.

His rule marked the formal integration of Sofia into the Ottoman administrative system, establishing a model for governance in newly conquered Balkan territories.

[12] Two years later, on 27 August 1388, Lala Shahin suffered another major defeat at the hands of the Bosnian Army of King Tvrtko I, commanded by Vlatko Vuković, at the Battle of Bileća.

[13][6] Some accounts suggest that Shahin had been dispatched by Murad I in response to a request for military support from George Stracimirović Balšić, the Lord of Zeta, who sought Ottoman assistance against Tvrtko.