The Jewish origin of the surname Miller stems from the German occupational name Müller (meaning "miller"), adopted by Ashkenazi Jews in German-speaking lands, becoming common due to historical requirements for surnames and a natural fit for a prevalent profession, also appearing as Yiddish Miller (מיללער) or Milner (מילנער). It's a very common Jewish surname in the U.S. (third after Cohen/Levy) and reflects assimilation, though many non-Jewish families also bear the name from German or English roots.

Key Points:

Occupational Origin: Like its English and German counterparts, the name describes someone who worked at a grain mill.

German Roots: In Jewish contexts, it's often a variation or anglicization of the German Müller, a common surname chosen for practicality when Jews were required to adopt hereditary names.

Yiddish Connection: The name exists in Yiddish as Miller or Milner, reflecting its Central/Eastern European Jewish history.

Commonality: It's one of the most frequent surnames in America, common among both Jewish and non-Jewish populations, including Amish and Mennonite families.

Assimilation: For Jewish families, adopting names like Miller was a way to integrate, making it a significant, albeit non-exclusive, marker of Jewish heritage.

(http://www.autoadmit.com/thread.php?thread_id=5826723&forum_id=2#49619296)