His father was not only a scientific jurist, but also a lawyer in large practice in Berlin. After working under his father, Hinschius in 1852 began to study jurisprudence at Heidelberg and Berlin, the teacher who had most influence upon him being Aemilius Ludwig Richter (1808–1864), to whom he afterwards ascribed the great utriusque juris, and in 1859 was admitted to the juridical faculty of Berlin. In 1863 he went as professor extraordinarius to Halle, returning in the same capacity to Berlin in 1865. In 1868, Hinschius became professor ordinarius at the University of Kiel, which he represented in the Prussian Upper House (1870–1871).
He also assisted his father in editing the Preussische Anwaltszeitung from 1862 to 1866 and the Zeitschrift fur Gesetzgebung and Rechtspflege in Preussen from 1867 to 1871. In 1872, he was appointed professor ordinarius of ecclesiastical law at Berlin.
In the same year he took part in the conferences of the ministry of ecclesiastical affairs, which issued in the famous "Falk Laws." In connexion with the developments of the Kulturkampf which resulted from the "Falk Laws," he wrote several treatises: e.g. on "The Attitude of the German State Governments towards the Decrees of the Vatican Council" (1871), on "The Prussian Church Laws of 1873" (1873), "The Prussian Church Laws of the years 1874 and 1875" (1875), and "The Prussian Church Law of 14th July 1880" (1881). He sat in the Reichstag as a National Liberal from 1872 to 1878, and again in 1881 and 1882, and from 1889 onwards he represented the University of Berlin in the Prussian Upper House.
The two great works by which Hinschius established his fame are the Decretales Pseudo-Isidorianae et capitula Angilrantni (2 parts, Leipzig, 1863) and Das Kirchenrecht der Katholiken and Protestanten in Deutschland, vols. i.-vi. (Berlin, 1869–1877). The first of these, for which during 1860 and 1861 he had gathered materials in Italy, Spain, France, England, Scotland, Ireland, the Netherlands and Belgium, was the first critical edition of the False Decretals.
His most monumental work, however, is the Kirchenrecht, which remains incomplete. The six volumes actually published (System des katholischen Kirchenrechts) cover only book i. of the work as planned; they are devoted to an exhaustive historical and analytical study of the Roman Catholic hierarchy and its government of the church. The work is planned with special reference to Germany; but in fact its scheme embraces the whole of the Roman Catholic organization in its principles and practice.
Unfortunately even this part of the work remains incomplete; two chapters of book i. and the whole of book ii., which was to have dealt with "the rights and duties of the members of the hierarchy," remain unwritten; the most notable omission is that of the ecclesiastical law in relation to the regular orders.
Incomplete as it is, however, the Kirchenrecht remains a work of the highest scientific authority. Epoch-making in its application of the modern historical method to the study of ecclesiastical law in its theory and practice, it has become the model for the younger school of canonists. See the articles by Emil Seckel in Herzog-Hauck, Realencyklopädie (3rd ed., 1900), and by Ulrich Stutz in the Allgemeine deutsche Biographie, vol. 50 (Leipzig, 1905).