He has five siblings: Alexander, Sam, Bill, Eija and Valter, and two half-brothers Ossian and Kolbjörn by his father's second marriage, to Megan Everett.

Gustaf decided to follow in his father's footsteps as an actor at the age of six and attended drama school.

Gustaf Skarsgård continued with several children's and youth roles, for example, Min vän Percys magiska gymnastikskor (1994) and Skuggornas hus (1996).

[6] In 2012, Skarsgård joined the History Channel's series Vikings in the main role of Floki, the shipbuilder.

[2] In March 2020, Skarsgård starred in a main role as Merlin, in Cursed, a Netflix original television series based on a re-imaging of the Arthurian legend.