He was politically active in the relatively conservative Hofgeismarer Kreis of the SPD and is believed to have authored the group's statement of principles.

In his short life, he was involved in a number of political debates and controversies, most notably with Hans Kelsen, Carl Schmitt and Max Adler.

He is generally perceived to have been a major influence on Carlo Schmid who, in turn, drafted most of the German Constitution and was the main force behind the reform of the SPD.

Heller was forced to go into exile to Spain in 1933 with his wife and children, and died in Madrid in the same year, leaving his magnum opus, Staatslehre, unfinished.

[citation needed] Among political scientists who study democracy, liberalism and authoritarianism, Heller's work has had a renewed interest in the 2010s and in the 2020s.