He was the son of Hazrat Abdullah ibn Amr ibn Haram al-Ansari, who was martyred at Gazwa Uhud. Jabir ibn Abdullah embraced Islam when he was a young boy. He loved the Holy Prophet dearly and kept close to him. He sacrificed his happiness for the welfare of his seven sisters. He was always repeating, that the Holy Prophet taught him that smiling in his brother's face was a good deed for which a believer would be rewarded by Allah. Although he was very poor, he sacrificed the dire food he had to the Holy Prophet who was tying two stones to his stomach to overcome the feeling of hunger. Hazrat Jabir took part in 18 campaigns headed by the Holy Prophet. He also narrated many Hadith.

After the Holy Prophet's death, he lived in Madina, where he lectured in the Masjid-e-Nabwi (The Prophet's Mosque), Egypt, and Damascus. Such leading Tabi'en scholars as Amr ibn Dinar, Mujahid, and Ata' ibn Abi Rabah attended his lectures. People gathered around him in Damascus and Egypt to learn of the Holy Prophet and his Hadith.