[1] He expanded the borders of the sultanate at the expense of his neighbors, particularly the Mengujek Beylik and the Ayyubids, and established a Seljuq presence on the Mediterranean with his acquisition of the port of Kalon Oros, later renamed Ala'iyya in his honor.

The sultan, sometimes styled Kayqubad the Great,[2] is remembered today for his rich architectural legacy and the brilliant court culture that flourished under his reign.

In the period following the mid-13th century Mongol invasion, inhabitants of Anatolia frequently looked back on his reign as a golden age, while the new rulers of the Anatolian beyliks sought to justify their own authority through pedigrees traced to him.

Kayqubad was the second son of Seljuk Sultan Kaykhusraw, who bestowed upon him at an early age the title malik and the governorship of the important central Anatolian town of Tokat.

Kayqubad initially garnered some allies among the neighbors of the sultanate: Leo I, the king of Cilician Armenia and Tughrilshah, the brothers' uncle and the independent ruler of Erzurum.

[6] In 1227/1228, Kayqubad advanced into Anatolia, where the arrival of Jalal ad-Din Mingburnu, who was fleeing the destruction of his Khwarezmian Empire by the Mongols, had created an unstable political situation.

He also put down a revolt by the Empire of Trebizond and, although he fell short of capturing their capital, forced the Komnenos dynasty family to renew their pledges of vassalage.

Many Muslim Sufis and poets such as Mūhyūddīn İbnūl-Arābī, Abd al-Laṭīf al-Baghdādī, Ahi Evran, Necmeddīn-i Dāyē, Kāniî-i Tūsī, Shihab al-Din 'Umar al-Suhrawardi and Sultanulūlemā Bâhâeddīn Veled came to Anatolia during his reign.