So the HouseOfNames was not that far off by saying that Segal originated in Germany. Some probably did.
Seigal originated in Germany. It's a completely different name, that by chance ended up sounding and looking the same. Ours is really a honorary title. We know this by certain other traits. My ancestral family profession was Kosher butchers. Kosher butchers were generally the richest people in the Jewish communities (especially in Belarus). This is because all meat had to be cut by us, ever Rabbi's couldn't do it. Even if you owned cows you had to come to us to get them slaughtered. The title of butcher was given to Levites only, and this was the most lucrative title to be given.
There is also a name called Seagal, which is of English origin, and also doesn't have any relation to us. Almost all the variations of our name a 100 years ago had only one vowel:
Segal, Sagal, Shagal, Segalchik, Segalevich, Segaliovich, Segalov, Segalovich, Segalovskij, "Segel, Segelman, Segelson, Segelevich, Segil, Seglin, Segolov-Shchegolev, Sejgal, Sejgalus, Sejgel, Sigal, Sigalchik, Sigalskij, Sgalov, Sigalovich, Sigalovskij, Sigalus, Sigolovich, Sycal, Sycalovskiy, Tsigal, Tsigal, Tsycal, Tsoglin, Salal, Dagalchik, Sagalin, Sagalov, Sagalovich, Sagalovskij, Sagelevich, Saglovskij, Sagol, Sagolovich, Sogalov, Sogalov-Shchegolev, Sogalovskij, Sogolov, Sogolovich, Sogolovskij, Shegal, Shegal, Shegalov, Shegelman, Shejgal, Shigalov, Shugal, Shugol, Shugul, Shagaliovich, Shagalov, Shagelman, Zegal, Zegelman, Zigal, Zigelman, Zygal, Zagel.
The other 2 versions started being used by some members of our clan after they moved outside of Eastern Europe. But origins of those two names are not related to our own. There is also Shagal in India, and even thought it is completely identical to my name (I'm from the Shagal/Chagall, as in Marc Chagall family) it is also completely unrelated. Just a coincidence.