English form, since the Middle Ages, of the French name Louis. In modern use it is also in part a transferred use of the surname derived from this given name, or from Anglicized forms of Gaelic Mac Lughaidh ‘son of Lughaidh’ or Welsh Llewelyn.
English and Scottish: patronymic from the personal name John. As an American family name, Johnson has absorbed patronymics and many other derivatives of this name in continental European languages. (For forms, see Hanks and Hodges 1988.)