After the death of Muhammad-bin-Tughlaq in 1351 Firoz Tughlaq had the unique distinction of being chosen as sultan by the nobles. He appointed Khan-i-Jahan Maqbal, a Telugu Brahmin convert as wazir (prime minister). The wazir helped the Sultan in his administration and maintained the prestige of the Sultanate during this period.
After his accession Firoz had to face the problem of preventing the disintegration of the Delhi Sultanate. He tried to safeguard his authority over north India instead of reasserting his authority over the Deccan and south India. He led two expeditions to Bengal but they were not successful. Bengal became free from the control of Delhi Sultanate. Firoz led a campaign against Jajnagar (modern Orissa). He returned with rich booty acquired from the temples. He marched against Nagarkot and made its ruler to pay tributes. During this campaign the Sultan collected 1300 Sanskrit manuscripts from the Jawalamukhi temple library and got them translated into Persian. Firoz next marched against Thatta in the Sind region and crushed a rebellion there.
The reign of Firoz Tughlaq was more notable for his administration. He strictly followed the advice of the ulemas in running the administration. He pleased the nobles and assured hereditary succession to their properties. Thus the iqta system was not only revived but also it was made hereditary. As per the Islamic law he levied the taxes. Jiziya was strictly imposed on non-Muslims. He was the first Sultan to impose irrigation tax. But at the same time he dug irrigation canals and wells. The longest canal was about 200 kilometres from Sutlej to Hansi. Another canal was between Yamuna and Hissar. There were about 1200 fruit gardens in and around Delhi yielding more revenue. The special tax on 28 items was abolished by him since they were against the Islamic law. He also developed royal factories called karkhanas in which thousands of slaves were employed. About 300 new towns were built during his reign. The famous among them was Firozabad near Red Fort in Delhi, now called Firoz Shah Kotla. Old monuments like Jama Masjid and Qutb-Minar were also repaired.
A new department called Diwan-i-Khairat was created to take care of orphans and widows. Free hospitals and marriage bureaus for poor Muslims were also established. Firoz patronized scholars like Barani and Afif. As he was guided by the ulemas, he was intolerant towards Shia Muslims and Sufis. He treated Hindus as second grade citizens and imposed Jiziya. In this respect he was the precursor of Sikandar Lodi and Aurangazeb. Also he increased the number of slaves by capturing the defeated soldiers and young persons. In his regime the number of slaves had increased to one lakh eighty thousand. When Firoz died in 1388 the struggle for power between the Sultan and the nobles started once again. His successors had to face the rebellion of the slaves created by Firoz.
In the following years, the Delhi Sultanate had disintegrated further. Many provinces like Malwa and Gujarat declared their independence. The invasion of Timur in 1398 had worsened the situation. When Timur entered Delhi there was no opposition and he sacked Delhi for three days murdering thousands of people and looting enormous wealth. He withdrew from India in 1399 and his invasion in fact delivered a death blow to the Tughlaq dynasty.