He revolted three times, twice almost captured the khanship and once partitioned the Khanate between himself and his uncle.
In 1523 his over-ambitious father, Mehmed I Girai was killed by the Nogais at Astrakhan.
In October, while returning with their loot, they were defeated by a Cossack flotilla while crossing the Dnieper.
He entered the Peninsula with a large army, took the capital of Kyrkor and declared himself khan.
Saadet fled to the Turkish garrison at Perekop, which Islam besieged in November.
In autumn several great nobles changed sides and Islam fled to the steppes.
In the spring of 1532 he was wandering beyond the Don, while Saadet unsuccessfully besieged Cherkassy.
The Turks made his uncle Sahib I Giray khan and Islam became Kalga, holding Perekop and Ochakov.
In August 1533 the new Kalga led 40000 men against Russia but was driven back near Ryazan.
The effect was to partition the Khanate, with Islam controlling the steppes north of Perekop and Sahib holding the peninsula.