During Mahmud's early reign, his vassal king Garshasp II, who was a favorite of his father Muhammad I, fell into disgrace.

[2] Ahmad then proceeded as far as Baghdad, whereupon Mahmud was married to one of Sanjar's daughters, made his uncle's heir, and forced to give up strategic territories in northern Persia.

In 1129 Mahmud officially recognized the authority of Imad al-Din Zengi, who had supported him against a revolt led by al-Mustarshid, caliph of Baghdad, in Syria and northern Iraq.

In around 1116, Mahmud was bethrothed to his cousin Mah-i Mulk Khatun, also known as Mahd-i Maymun, the daughter of his uncle Sultan Ahmad Sanjar.

The blaze resulted in Mah-i Mulk losing precious possessions, including jewels, ornaments, furnishings, and clothing.

[6] Another wife, who was the mother of Mahmud's son, Alp Arslan, died while living at the residence of Aq Sunqur al-Bursuqi.

[16] According to Ann Lambton, Zahida Khatun, the wife of Atabeg Boz-aba was probably the mother of Mahmud's son Muhammad.

[19] His sons were Dawud,[20] Malik-Shah III,[21] Muhammad II,[22] Alp Arslan, Farrukh Shah[23] and Ala al-Daula Ata Khan.