According to Genesis, Shem is the first son listed in Noah’s post-flood genealogy.
Genesis 10:1 begins its table of nations with “the sons of Noah, Shem, Ham, and Japheth” after the flood. Genesis 11 then follows Shem’s descendants through Arpachshad, Shelah, Eber, and later generations to Terah and Abram. This makes Shem’s line especially prominent within the biblical narrative.
The wording “first listed” matters because name order and birth order are not always identical. Genesis presents the three brothers in a particular literary order, but readers should not automatically treat that order as a definitive age ranking.
Shem is also the eponymous ancestor associated with the later term Semitic. That modern term refers to a language family and related historical categories, not to a single ancient ethnicity defined solely by the Genesis genealogy.