Eythor Ingi's parents are Gunnlaugur Antonsson, a fisherman and Guðbjörg Stefánsdóttir, a housewife and student. He also has two younger sisters, Ellen Ýr and Elísa Rún. His grandfathers Anton Gunnlaugsson and Stefán Friðgeirsson were both musicians, influencing Eythor to make music. Eythor Ingi's first idol was Elvis Presley and recalls imitating him in bad English.
Eythor Ingi is also dyslexic and has ADHD, which he slightly refers to in the lyrics of Ég á líf. In the official music video for his Eurovision song, he is seen fishing and filleting a fish, so he has presumably been taught some skills by his father.
- Eythor Ingi was a part of the voice cast of the Icelandic dub of the film "How To Train Your Dragon 2", where 2009 winner Alexander Rybak performed the part of Hiccup in the Norwegian dub, and recorded the theme song "Into A Fantasy".