Heinemann was named after his mother's father, a master roof tiler in Barmen, with radical-democratic, left-liberal, and patriotic views.

[1] Having finished his elite secondary education in 1917, Heinemann briefly became a soldier in the First World War, but his severe illness stopped him from being sent to the front.

From 1918, Heinemann studied law, economics, and history at the universities of Münster, Marburg, Munich, Göttingen, and Berlin, graduating in 1922 and passing the bar in 1926.

Among his friends were such different people as Wilhelm Röpke, who was to become one of the leading figures of economic liberalism, Ernst Lemmer, later a trade unionist and also a Christian Democrat, and Viktor Agartz, a Marxist.

[2] Through his sister-in-law, he became acquainted with Swiss theologian Karl Barth, who strongly influenced him such as in his condemnation of nationalism and antisemitism.

[4] Information sheets of the Confessing Church were printed in the cellar of Heinemann's house at Schinkelstrasse 34 in Essen, Moltkeviertel, and distributed all over Germany.

In 1949, he was also one of the founding editors of Die Stimme der Gemeinde ("The Voice of the Congregation"), a magazine which was published by the Bruderrat (Brethren's Council) of the Confessing Church.

When Konrad Adenauer became the first Chancellor of the newly founded Federal Republic of Germany in 1949, he wanted a representative of the Protestants in the CDU in his government.

Heinemann, the president of the Synod of Protestant Churches, reluctantly agreed to become the Minister of the Interior although he had planned to resume his career in industry.

[6] A year later, when it became known that Adenauer had secretly offered German participation in a Western European army, Heinemann resigned from the government.

He was convinced that any form of armament in West Germany would diminish the chances of German reunification and increase the risk of war.

They advocated negotiations with the Soviet Union with the aim of a reunited, neutral Germany between the blocs, but the GVP failed to attract many voters.

He established the tradition of inviting ordinary citizens to the president's New Year's receptions, and in his speeches, he encouraged West Germans to overcome the tradition of submissiveness to the authorities, to make full use of their democratic rights and to defend the rule of law and social justice.

[4] It was Heinemann's idea to found a museum for the commemoration of German liberation movements, and he was able to open such a place officially in Rastatt in 1974.

A short time before his death, Heinemann published an essay in which he criticized the Radikalenerlass ("Radicals Decree") of 1972, a rule that subjected all candidates for the civil service (including prospective teachers, railway engine drivers, and postmen) to special scrutiny to exclude political radicals.