The Partenopei headed into the last round of fixtures in the Serie A on Sunday sitting in fourth place, with Juventus breathing down their neck but a 1-1 home draw against Hellas Verona saw Andrea Pirlo’s side steal the final Champions League spot thanks to a 4-1 win away at Bologna.
It means that for the second season running under Gattuso, Napoli will have to contend with Europa League football for next season.
Gattuso joined Napoli in December 2019, replacing Carlo Ancelotti and led them to a seventh place finish in Serie A and a Coppa Italia triumph over Juventus.
The 43-year-old’s contract would have expired later this summer but club president Aurelio De Laurentiis tweeted right after Sunday’s game that both parties will be going their separate ways.
'Dear Rino, I am happy to have spent almost two seasons with you. Thank you for your work and I wish you success wherever you go. A hug also to your wife and children,' De Laurentiis wrote on Twitter after the game.
Napoli were also knocked out of this season’s Europa League at the round of 32 stage by Spanish La Liga side Granada.