The eldest son and successor of Ala ad-Din Muhammad II of the Khwarazmian Empire, Jalal al-Din was brought up at Gurganj, the wealthy capital of the Khwarazmid homeland.

An able general, he served as second-in-command to his father in at least one battle; however, since he was the son of a concubine, he was challenged as successor by a younger brother, whose cause was supported by the powerful Queen Mother, Terken Khatun.

He managed to inflict an excellent defeat on Shigi Qutuqu at the Battle of Parwan, but soon lost a good portion of his army in a dispute over spoils.

Now essentially a warlord, Jalal al-Din managed to establish a succession of short-lived states: first in the Punjab from 1222 to 1224, and then in northwest Iran and Georgia after 1225.

[3]: 142 Jalal al-Din was reportedly the eldest son of the Khwarazmshah Ala ad-Din Muhammad II (r. 1200–1220),[4] while his mother was a concubine of Turkmen origin, whose name was Ay-Chichek.

[12] The Shah thus made the decision to distribute his forces as garrison troops inside his most important towns, such as Samarkand, Merv and Nishapur.

Genghis Khan then sent an army under his elite generals Jebe and Subutai specifically to pursue the Shah; although Muhammad, accompanied by Jalal-al Din and two other sons, managed to escape, he was prevented from gathering any forces as his empire collapsed around him.

[9]: 432  Crossing the Karakum Desert, he attacked the garrison of a Mongol detachment at Nesa, killing most of the force including two brothers of Toghachar, son in law of Genghis Khan.

[6]: 295  The Mongols pursued, past Nishapur and Herat, but lost the trail before Ghazni, where Jalal al-Din found 50,000 loyalists waiting for him.

After a few days, he was joined by his maternal uncle Temur Malik, who brought an additional 30,000 veterans – Jalal al-Din now had a sizeable force with which to strike back at the Mongols.

[10]: 150–2 Jalal al-Din, who had just married Temur Malik's daughter to solidify ties, marched towards Kandahar which was under siege by a Mongol army and defeated them after a two-day battle.

[14] This battle made Jalal al-Din's reputation; however, he soon lost half of his army through infighting: the sources report a dispute over booty between Temur Malik and Ighrak, commander of the right flank.

[3] Jalal al-Din had won several victories against the Mongols in 1221, and after the Battle of Parwan, independent insurgency groups emerged in multiple cities inspired by his deeds.

Kushteghin Pahlawan launched a revolt in Merv and ousted the Mongol administration; he then made a successful attack on Bukhara, while Herat also rebelled.

[15] Under Doqshin's leadership, the Mongol army took Nandana fort of Janjua tribe from one of the lieutenants of Jalal ad-Din, sacked it, then proceeded to besiege the larger Multan.

[15] Having gathered an army and entered Persia, Jalal ad-Din sought to re-establish the Khwarazm kingdom, but he never fully consolidated his power.

In 1224, he confirmed Burak Hadjib, ruler of the Qara Khitai, in Kerman, and received the submission of his brother Ghiyath, who had established himself in Hamadan and Isfahan, and the province of Fars, and clashed with the Caliph An Nasser in Khuzestan, from whom he captured parts of Western Iran.

That same year, he attacked Georgia, defeating its forces in the battle of Garni, and captured Tbilisi,[13]: 260  after which a hundred thousand citizens were put to death for not renouncing Christianity.

In 1227, after the death of Genghis Khan, a new Mongol army commanded by Chormagan was sent to invade al Din's lands; they were met near Dameghan and defeated.

His biographer, Shihab al-Din Muhammad al-Nasawi, described him as follows: He was swarthy (dark-skinned), small in stature, Turkic in "behavior" and speech, but he also spoke Persian.

[7] Due to his reputation for resisting the Mongols, Jalal al-Din is commonly depicted on artwork resembling that of the Persian epic Shahnameh, where he is associated with the mythological warrior Rostam.

[27] Jalal al-Din was the subject of the Uzbek-Turkish TV series Mendirman Jaloliddin, created by Mehmet Bozdağ in collaboration with the Uzbek Ministry of Culture and Sports, where he was played by Emre Kıvılcım.