[3] When Heuser was one year old his father ran off with his neighbor's wife, emigrated to New Braunfels, Texas and changed his name to Eugen Kailer.

On 11 October 1907 he married in Düsseldorf, to Mira Sohn-Rethel, the daughter of painter Karl Rudolf Sohn.

In 1919, Heuser was one of the first members of the Young Rhineland (Das Junge Rheinland) artists' group, alongside Heinrich Nauen, Adolf Uzarski, Arthur Kaufmann, Carlo Mense, Walter Ophey, and architect Wilhelm Kreis.

Some of his students included Herbert Zangs,[7] Else Harney,[8] Georg Meistermann,[9] Caspar Walter Rauh,[10] among others.

[11] Starting in 1933, the group labeled modern artwork and artists as "Jewish," "degenerate," and "Bolshevik".

[11] In 1937, the Nazi officials purged German museums and removed the art they considered to be degenerate and formed a special exhibit of the work called, Entartete Kunst.