Bernard was the son of Frederick the Pious and his wife Magdalene of Brandenburg. In 1452, Bernard was elected at the request of the Bishop of Hildesheim to be his coadjutor and later became his successor when the bishop died. However, the bishop's aspiration that in selecting a Welf the bishopric would strengthen its position vis-a-vis the Welf Principality of Brunswick-Wolfenbüttel proved elusive because Bernard felt obliged to support the interests of his family first. At the request of his father, he left the bishopric in 1457 to take over the Principality of Lüneburg, which he ruled jointly with his brother, Otto the Victorious, until his death on 9 Feb 1464. He married Matilda of Holstein-Schauenburg, daughter of Otto II, Count of Schauenburg-Pinneberg, in 1463, but the marriage was childless. Matilda went on to be the second wife of William the Victorious, Duke of Brunswick-Lüneburg.
- Die Diözese Hildesheim. In Vergangenheit und Gegenwart von Thomas Scharf-Wrede ISBN 3-7954-1721-X
- Geckler, Christa (1986). Die Celler Herzöge: Leben und Wirken 1371–1705. Celle: Georg Ströher. ISBN 3-921744-05-8. OCLC 255990175.
- Ferdinand Spehr (1875), "Bernhard von Braunschweig-Lüneburg", Allgemeine Deutsche Biographie (ADB) (in German), vol. 2, Leipzig: Duncker & Humblot, p. 418