Transferred use of the Welsh surname, in origin a variant of Lloyd. This form of the name results from an attempt to represent the sound of the Welsh initial Ll- using traditional English pronunciation and orthography. From the 1890s to the 1930s it was at its most popular in the United States.
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.)