Shem is traditionally described in Genesis as the ancestor of the Hebrews.
Genesis 10 presents a table of nations descended from Noah’s three sons: Shem, Ham, and Japheth. Genesis 11 then traces the line from Shem through several generations to Abram, later called Abraham. Because the Hebrew patriarchal line is traced through Shem, the term “Semitic” was later formed from his name, although modern linguistics uses “Semitic” for a language family rather than as a simple biological ancestry label.
Ham is associated in Genesis with descendants including Cush, Egypt, Put, and Canaan, while Japheth’s descendants are listed separately. The text does not call every descendant of Shem a Hebrew, but it places the ancestry of Abraham’s line within the genealogy of Shem. This is why Shem is the canonical answer to the question.