Jalaluddin Khalji was the founder of the Khalji Dynasty. He came to power after the over throw of the slave dynasty. Thus the coming of the Khaljis to power was more than a dynastic change. Their ascendency is known as the Khalji imperialism because with the accession of Jalaluddin Khalji on the throne of Delhi the supremacy of the Turks ended in India.Jalaluddin ascended the throne at the age of 70 years and the weakness of the old age affected his attitude and activities. He was lenient in his treatment of rebels .He even adopted a conciliatory policy towards the Mongols. He allowed some of the Mongols to settle in India.
Jalaluddin's ambitious nephew Alauddin who succeeded Malik Chajju at Kara began to establish an independent kingdom for himself. In 1292 AD he attacked Bhilsa and Malwa.On his return he was made the governor of Avadh in addition to that of Kara. In 1294 AD he defeated Ram Chandra Deva the ruler of Devagiri.He invited Jalaluddin to Kara where he was murdered by Alauddin Khalji.In 1296 AD Alauddin was proclaimed sultan in his camp. He marched to Delhi from Kara and assumed power at Delhi. His first task after assuming power at Delhi was the elimination of the surviving members of the former sultan's family including his son Arkhali Khan. He also exterminated the old Balbani and Jalali nobles.
The reign of Alauddin Khalji marks the zenith of the power of the Delhi Sultanate. Since the death of Iltutmish no serious attempts had been made to annex new territories to the Sultanate. He broke this tradition and inaugurated a whirlwind period of conquests. He believed that defense, expansion and consolidation could all go together. By the end of 1305 AD the whole of northern India fell into the hands of Alauddin and he directed his energies to the conquest of Deccan. Between 1307 and 1312 he began the southward expansion of his empire. He invaded Devagiri in 1306-07.The immediate causes for this was unduly long delay in sending the annual tribute. In 1309 the Kaktiya kingdom was attacked. The next expedition was against Vira Ballala III the Hoysala ruler in 1311.Alauddin had to face more than dozen invasions. These invasions started from the end of 1296 AD and continued up to 1308 AD.The Mongols threatened Punjab, Multan and Sindh but also the Ganga Yamuna Doab. This grave crisis compelled him to take strong measures for the protection of the northwest frontier. The twenty years rule of Alauddin came to an end with his death in 1316 AD.
On the death of Alauddin Khalji his general Malik Kafur set aside the claims of the heir apparent Khizr Khan and crowned the infant son of late sultan Shihabuddin Umar and himself became his regent. Soon another son of the sultan murdered Kafur and ascended the throne as Qutubuddin Mubarak Shah Khalji. He tried to win the goodwill of the people after ascending the throne. He repealed Alauddin's economic regulations. The lands that were confiscated were given back to their legitimate owners. Taxes were lowered. He was murdered by his Wazir Khusro.Khusro ascended the throne in 1320 and took the title of Nasiruddin Khusro Shah. Thus Khalji dynasty came to an end.