Mordechai Dovid Unger

Unger was born to Yaakov Yitzchok Unger of Dombrov.^[1][2] He is the younger son-in-law of Naftali Zvi Halberstam, the fourth Bobover Rebbe.^[1]

Following the death of his father-in-law right before the Purim holiday in 2005,^[3] a dispute arose as to who should be the Grand Rebbe of the then 120,000 Bobov Hasidim worldwide.^[1] While the majority began to follow Ben Zion Aryeh Leibish Halberstam, his father-in-law's half-brother,^[1] others followed the older (by one year) Unger, who had by then already ensconced himself firmly within the community.^[1] Unger could not challenge his own father for leadership of Dombrov, which anyway was not as substantial a dynasty as Bobov.^[4] The matter of succession was brought before a beth din (religious court) in 2007, which ruled that Halberstam would be declared Rebbe of Bobov (אדמו"ר מבאבוב) with its headquarters on 48th Street in Borough Park, Brooklyn,^[5] while Unger would be Rebbe of Bobov-45 (אדמו"ר מבאבוב-45), located on 49th Street.^[5][6]

1. Shlomo Halberstam (1847–1905), grandson of the Sanzer Rebbe, Chaim Halberstam
2. Ben Zion Halberstam (1874–1941)
3. Shlomo Halberstam (1907–2000)
4. Naftali Halberstam (1931–2005)
5. Mordechai Dovid Unger (b. 1954), son-in-law of Naftali Halberstam

Brooklyn Borough President Eric Adams visited Bobov–45 as part of his 2017 re-election campaign.^[7]