Actually no. :-)
There are several possibilities:
1. His father came to America with the name Miller from Poland. Miller, Millerowicz, Millerowicz, Millert, with double LL, also exist in Poland. As Polonius already stated there are 6000 people of that name currently living in Poland.
2. His father came to America with the name Müller from Poland(?), which has been later anglicized to Miller. He could be brought as a Pole, even though his name was German. We know of many such cases: General Anders, General Juliusz Rómmel, Christine von Habsburg (*), etc.
3. We actually do not know, whether his father is the first generation immigrant. And that opens up to many possibilities, such as German Grandpa, Polish Grandma, bringing his father up as a Pole, etc.
When the village invited me to return, I did not think of it twice. No hesitation. I sold my apartment in Switzerland and moved to Zywiec. I am very happy here where I am treated like a queen, a Habsburg who is completely Polish!," said the princess.
I just want to add this:
during the partitions names were actually germanized, not polonized.
Most of the time - yes. But the reverse process existed in many communities.
Some examples include names of Catholic Bambers, settled around Poznań. The current mayor of Luboń, south of Poznań, Dariusz Szmyt is a descendant of one of the first 60 Bambers that settled there, Karol Józef Schmidt.
The Poznań city scribe, Jan Rzepecki, wrote in 1730s a settler contract between owners of Dębiec, south of Poznań, and the 16 Bamber families. He spelled their names the way he heard them. They were illiterate, they signed the contracts with crosses and they were in no position to check their names spellings. Only later the German spelling was reintroduced by the Prussian oficials:
1 - Andrzej Hirsz z żoną Dorotą i dziećmi
2 - Piotr Wagner z żoną Elżbietą i dziećmi
3 - Jan Remlei z żoną i dziećmi
4 - Michałowa Ferczowa, imieniem Kunegunda, wdowa z dziećmi
5 - Jan Szmdt z żoną Małgorzatą i dziećmi
6 - Hans Jurga Ruth z żoną Anną i dziećmi
7 - Michał Hiller z żoną Dorotą i dziećmi
8 - Jan Baierlam z żoną Kunegundą i dziećmi
9 - Kasper Rysz z żoną Barbarą i dziećmi
10 - Hans Sznayder z żoną Anną i dziećmi
11 - Frans Hirsz z żoną Katarzyną i dziećmi
12 - Jurga Hirsz z żoną Maryanną i dziećmi
13 - Adam Petz z żoną Barbarą i dziećmi
14 - Konrad Sznayder, syn Hansa Sznaydra, z żoną Marianną
15 - Elżbieta Fischerowa, wdowa z dziećmi
16 - Frydrych Sznayder, syn Hansa Sznaydra, z żoną Magdaleną i dziećmi
Another example involves descendants of Taubdeutsche, Walddeutsche (Polish: Głuchoniemcy) settled in Lesser Poland, Jasło Pits, around XIV c. and later, and finally becoming Polonized around XVI c. The Polish wikipedia page,
provides a long list of polonized surnames., such as: