[2][3][4] Árni Óli's career began with the celebrated short film Anna's Day (Annas dag), which won the International Award at the Clermont-Ferrand International Short Film Festival in 2003.

[2] His first feature film was Thicker Than Water (Blóðbönd), which won the Special Prize of the Jury at International Filmfestival Mannheim-Heidelberg.

[2] Árni Óli's third feature as director was the animated film Ploey: You Never Fly Alone (Lói: Þú flýgur aldrei einn) in 2018, the most expensive Icelandic film ever made.

[6] His final feature film was the Polish-Icelandic production Wolka, released after his death in 2021.

[8] In February 2021, Árni Óli was diagnosed with a rare form of bone cancer.