His father, Sheikh Yusufzâde Hâlid Efendi,[1] was a member of the honorable judiciary and served as Kazasker and a minister.

On 4 September 1891, at 43, he was appointed Şeyhülislam, the Cabinet Minister in charge of religious and legal matters.

He was later reappointed on three other occasions for shorter periods, holding this post for nearly 18 years and becoming the second-longest holder in Ottoman history after Zembilli Ali Efendi.

Mehmet Cemaleddin's younger brother, Ibrahim Sami Bey, was a member of the Ottoman Council of State, whose grandson Erol Gelenbe held the Dennis Gabor Chair (2003-2019) at Imperial College, London.

An opponent of the pro-German and war-oriented policy of the Union and Progress Party, Mehmed Cemalettin Efendi was exiled to Egypt in 1913 and died in a place called Ramleh near Menouf in Egypt on 5 April 1917 at the age of 70.