He is the imam of the Shāfiʿīs. His real name is Aḥmad b. Muḥammad. In his time, he was a leading figure in the Shāfiʿī madhhab. He was born in the year 344 AH. At a young age, in 363 or 364 AH, he came to Baghdad. He learned fiqh from Abū al-Ḥasan b. Marzubān. Then he took lessons from Abū'l-Qāsim al-Dāriqī. These circumstances advanced him. Eventually, he attained the rank of leadership among the Shāfiʿīs. His prestige grew among the sultan and the public. He was a faqīh and an imam. He was a person of noble stature and high dignity. His disciple wrote a fifty-volume sharḥ (commentary) on his work titled Talīb. He also has another taʿlīq (marginal commentary) on uṣūl al-fiqh. He transmitted from Ismāʿīlī and others. Ḥātib al-Baghdādī said: "I saw him several times. I attended his study circle. He was teaching in the mosque located in the Qātiʿat al-Rabīʿ district of ʿAbdallāh b. Mubārak. ʿIzz al-Dīn and Ḥallāl narrated ḥadīths from him to us. I heard that 700 fiqh students attended his study circle. People said about him, 'If Imam Shāfiʿī had seen him, he would have been very pleased.' Abū al-Ḥasan al-Quddūrī said: 'I have not seen anyone in the Shāfiʿī madhhab who knows fiqh better than Abū Ḥāmid.' About him, he said, 'Abū Ḥāmid was more insightful and knew fiqh better than Imam Shāfiʿī.'"
Abū Isḥāq also said: "This statement is not only al-Quddūrī's opinion. Because Abū Ḥāmid and his likes are in the situation described by the poet in relation to Imam Shāfiʿī:
"They stayed among the Nawfal tribes in Mecca.
But I stayed in the desert far from the houses."
Ibn Ḥallīkān said: "Abū Ḥāmid has works such as al-Taʿlīqāt al-Kubrā and Kitāb al-Bustān. Kitāb al-Bustān is a small work but contains rare knowledge. During some debates, jurists attacked him, but Shaykh Abū Ḥāmid responded to them with this poem:
"An openly occurring and widespread hardship in the presence of the people.
On the other hand, a secretly begged excuse. This excuse only strengthens the fault.
The one who thinks he can erase all his hardships by secretly begging forgiveness has fallen into a greater error."
Abū Ḥāmid al-Isfarāyinī died on a Saturday night, eleven days before the end of the month of Shawwāl of that year. After the funeral prayer was performed in the desert, he was buried in his own house. Many people attended his funeral. He was mourned greatly. Later, in 411 AH, he was transferred to the cemetery of Bāb al-Ḥarb.
According to Ibn al-Jawzī, he lived for sixty-one years and a few months.