Was Hitler Jewish?

"Was Hitler Jewish?" is a frequently asked question but it is one that requires clarification to answer correctly.  In essence, it encompasses two related sub-questions:  "did Hitler have Jewish origins/family members?" and "was Hitler himself Jewish?"

To begin with the second question—technically, in order to be Jewish, one must be born of a Jewish mother, or convert to Judaism (of course, the Nazis had their own ideas on what made someone a Jew).  Hitler was born to a Catholic mother, and obviously never converted to Judaism.  During his lifetime he was more or less a lapsed Catholic, at times dabbling in various German pagan-mystic beliefs.  Hitler became a vehement racist and anti-Semite, and promoting a vision of the "Jewish threat," he ultimately sought the extermination of the Jewish population of Europe.

As for the question of Jewish origins, Ian Kershaw, Hitler's highly acclaimed most recent biographer, points out that the belief that Hitler had a Jewish family member began amongst the rumors, sensationalist journalism, and claims of political rivals, even within the Nazi Party, of the 1920s and ‘30s.  The exact family member in question is Hitler's paternal grandfather, whose exact identity remains unknown to this day.  Hitler's father was Alois Shicklgruber.  On his 1837 baptismal record, Alois' mother, Maria Anna Shicklgruber, was recorded but there was no entry for a father.  Five years later Anna married Johann Georg Hiedler but following both of their deaths, Alois was taken in by Georg's brother, Johann Nepomuk Hiedler.  In 1876, Alois was made an heir to Nepomuk's legacy, following his taking of the family name of 'Heidler,' recorded as 'Hitler' through the official, ceremonial acknowledgement of Georg Hiedler as Alois' father. 

The more consequential claim, which caused popular debate, was issued by Hans Frank, a Nazi lawyer whom Hitler had asked to investigate his ancestry, and who published his alleged findings while waiting execution at Nuremburg.  This is the famous "Graz story", which asserted that Hitler's grandmother, Maria Anna Shicklgruber, had been employed by a Jewish family, the Frankenbergers, in the city of Graz, and that there was correspondence and even child support payments exchanged between the family and Maria.  However, Kershaw highlights that this story is highly inaccurate as there is no record that Maria was ever in Graz.  Furthermore, while there was a family of a similar last name in Graz, they were not Jewish—especially given that Jews were not even permitted in that section of Austria (Styria) until the 1860s.

Ultimately, the answer to the question, in both of its forms, is a definitive 'no.'