[4] A narrator of hadith, he was known for being extremely strict against the Jahmi and Karami schools of thought which prevailed during his time.

[1][3] His best known work is the Naqd 'Uthman ibn Sa'id 'alal-Marisi al-Jahmi al-Anid, a detailed refutation against one of his contemporaries, Bishr al-Marisi.

[4][2] Uthman ibn Sa'id al-Darimi was known for his aggression against the Jahmi school.

[6] His writings were quoted by later traditionist Athari scholars like Ibn Taymiyyah.

[6] His persistent efforts to defame the Karamiyyah resulted in their founder, Ibn Karram, being expelled from Nishapur.