Following the governor's death in 1528, Sher Shah obtained a high position in Bihar and, by 1530, became the regent and de facto ruler of the kingdom.
In 1538, while Mughal Emperor Humayun was engaged in military campaigns elsewhere, Sher Shah overran the Bengal Sultanate and established the Suri dynasty.
As ruler of Hindustan, Sher Shah led numerous military campaigns, conquering Punjab, Malwa, Marwar, Mewar, and Bundelkhand.
He issued the first Rupiya, organized the postal system of the Indian subcontinent, as well as extending the Grand Trunk Road from Chittagong in Bengal to Kabul in Afghanistan, significantly improving trade.
The name Sher (means lion in Persian) was conferred upon him for his courage when, as a young man, he killed a tiger that leapt suddenly upon the governor of Bihar, Behar Khan Lohani.
[12][13] Sher Shah's grandfather, Ibrahim Khan Sur, began his career as a horse trader and eventually became a landlord (Jagirdar) in the Narnaul area of present-day Haryana.
One of Sher Shah's significant reforms as administrator of his father's domains was the assessment of land revenues, along with defining and establishing commissions for tax collectors.
Conflict emerged however over the split of his father's land between his brothers, and Muhammad Khan Sur initially drove Sher Shah from the estate by defeating one of his governors.
Babur took notice and informed his minister, Mir Khalifa: Keep an eye on Sher Khan, he is a clever man and the marks of royalty are visible on his forehead.
I have seen many Afghan nobles, greater men than he, but they never made an impression on me, but as soon as I saw this man, it entered into my mind that he ought to be arrested for I find in him the qualities of greatness and the marks of mightiness.
Sher Shah was appointed as her deputy governor, allowing him to begin consolidating his position in the region through a myriad of military and administrative reforms.
Intending for the unification of all Afghan leaders, Mahmud marched with his army to Sasaram, persuading Sher Shah to join the rebellion.
Hesitatingly, Sher Shah accompanied the expedition with his own set of men, and the insurrection initially succeeded, capturing Ghazipur and Banaras.
[32] In early 1530, the death of Dudu Bibi enabled Sher Shah to become the regent for Jalal Khan, effectively making him the de facto ruler of Bihar.
Humayun accepted and lifted the siege in December 1532, returning to Agra due to the rising threat of Bahadur Shah, the ruler of the Gujarat Sultanate.
[53] After the fall of Gauda, Sher Shah offered favorable peace terms to Humayun, proposing to pay 10,000,000 dinars, and cede Bihar in exchange for control of Bengal.
Following this victory, Sher Shah was crowned a second time on 17 May 1540, being declared the ruler of Hindustan and adopting the epithet Sultan Adil, meaning "Just King."
The pursuit and flight of Humayun allowed Sher Shah to capture and enter Delhi, beginning the consolidation of his rule there by reorganizing its administration.
Qadir Khan, the ruler of the Malwa Sultanate, had offended Sher Shah by claiming he was equal to him, as well as failing pledged aid against the Mughals.
Sher Shah thus resorted to intrigue by dropping forged letters near Maldeo's camp, falsely indicating that some of his commanders intended to defect to the Afghans.
[80] Following the victory, Khawas Khan Marwat took possession of Jodhpur and occupied the territory of Marwar from Ajmer to Mount Abu in 1544, with Bikaner also submitting to Afghan rule.
[62][84] At the end of his reign, Sher Shah's empire spanned nearly the entirety of Northern India, excluding Assam, Kashmir, Gujarat, and the North-West Frontier Province.
Written by Abbas Sarwani, the source was significant toward detailing the conquest of Bengal by Sher Shah as well as the magnitude of his reforms, and greatly benefited in contribution towards the history of medieval India.
Sikander Shah attempted to give battle to Humayun at Sirhind before being defeated as well, allowing the Mughals to re-occupy Delhi.
[98] The Rupee is today used as the national currency in India, Indonesia, the Maldives, Mauritius, Nepal, Pakistan, the Seychelles, and Sri Lanka.
[107][17] Srivastava elaborates, stating that Sher Shah's balanced approach satisfied his fellow Muslims despite his lenient treatment of Hindus.
[108] Noted by historians as an excellent military leader,[101] Sher Shah invited Afghans from across the empire as well as Afghanistan, giving them high positions and personally taking an interest in recruiting troops.
[117][118] Sher Shah's reputation grew as he became known for being a formidable and just ruler, to the point where merchants could travel and sleep in deserts without fear of being harassed by bandits or robbers.
Sher Shah Suri also implemented the reform of self-responsibility, assigning officials the duty to find culprits in cases such as murder; if they failed, they would be held responsible and hanged.
[119][127] Sher Khan (1962), an Indian Hindi-language action film by Radhakant starring Kamaljeet in the titular role along with Kumkum, is ostensibly based on the emperor's life.