Are Jews legalistic?
Traditional Jews follow halakha [Jewish law, a set of ideas that expresses their Jewish identity] as a guideline that determines much of their life, from the food they eat, the way it’s eaten to family law and opinions on organ transplants or fertility treatment. Judaism, like Islam, is an orthopractic tradition that stresses doing (praxis) over believing, although action should be accompanied by proper intentions. For Jews, this means following divine law, but outsiders often regard Judaism as legalistic, a term most Jews reject as anti-Jewish because of its connections to supercessionist theologies, i.e. the idea that Christianity has superceded (replaced) Israel as God’s people.
But note: Although Christians often emphasize that action comes from belief–cf. Martin Luther’s “Good works don’t make a good man, but a good man bears good fruit”–the Epistle of James insisted that “faith without works is dead”—not so different from the Jewish concept!
How can Jews follow a different set of “laws” and still be Americans?
A central principle of halakha (Jewish law) is called “the law of the land is law.” It recognizes non-Jewish laws and non-Jewish legal jurisdiction as binding on Jewish citizens, provided that they are not contrary to any laws of Judaism. This applies especially in areas of commercial, civil and criminal law and is widely observed.
For a modern application see the orthodox discussion on Intellectual Property here.