He was a close friend of Ahmad ibn Hanbal and is often quoted regarding Ilm ar-Rijal. Alongside Ibn Hanbal, Ali ibn al-Madini and Ibn Abi Shaybah, Ibn Ma'in has been considered by many Muslim specialists in hadith to be one of the four most significant authors in the field.
His teachers included; Ibn al-Mub?rak, Isml ibn ?Iy?sh, 'Ab?d ibn 'Ab?d, Sufy?n ibn ?Uyainah, Gundur, Ab? Muwiyyah, tim ibn Isml, ?af? ibn Giy?th, Jar?r ibn ?Abdul-?am?d, 'Abd ur-Ruzz?q, Wak?' and many others from Ir?q, ?ij?z, Jaz?rah, Sh?m and Mi?r.
From amongst his students were; A?mad bin ?anbal, Mu?ammad bin S?ad, Ab? Khaithamah, al-Bukh?r?, Muslim, Ab? D?w?d, ?Abb?s al-Dawr?, Ab? tim, and many others.
His zeal for knowledge was recognised through his endeavours. A notable example is that after the passing of his father he inherited 1,050,000 dirhams. He spent it all towards seeking ?ad?th to the extent that nothing remained to even purchase a pair of shoes.
We also see the Im?m's zeal for seeking knowledge by the various journeys he made, such as: Basrah, Bagd?d, Har?n, Dimasq, al-Ras?fah, al-Ray, San', Kuf?, Mi?r and Makkah al-Mukaramah.
His works were not limited to mere approbations and disapprobation of narrators albeit a science he was a master in, or narrating of ad?th, rather, he progressed forward as an author writing many books, many of which are not found today, despite him formally writing as an author at the age of twenty. Of the books available today are; Ma'rifatul al-Rij?l, T?r?kh ?Uthm?n bin Sad al-D?rim?, Ya?y? bin Man wa Kit?buhu 'l-T?r?kh and a small treatise titled 'Min Kal?m Ab? Zakariyy? Ya?y? bin Man fi 'l-Rij?l'.