This name was sometimes used as a personal name, and was borne by a few early saints, including a Roman soldier martyred with Nereus in the 1st century.
According to Genesis in the Old Testament Adam was created from the earth by God (there is a word play on Hebrew אֲדָמָה (ʾaḏama) meaning "earth"). He and Eve were supposedly the first humans, living happily in the Garden of Eden until they ate the forbidden fruit from the tree of knowledge of good and evil. As a result they were expelled from Eden to the lands to the east, where they gave birth to the second generation, including Cain, Abel and Seth.
As an English Christian name, Adam has been common since the Middle Ages, and it received a boost after the Protestant Reformation. A famous bearer was Scottish economist Adam Smith (1723-1790).
This name has been used occasionally in England since the 12th century. It was not common in the English-speaking world until the end of the 20th century.