The 20-year-old, who has represented the Republic of Ireland at Under-17 and Under-19 levels, has put pen to paper on a two-year deal at the Caledonian Stadium.
Inverness manager Richie Foran told the club's website: "We are delighted to get Jake tied up on a pre-contract. He brings something different to the squad. He has plenty of pace and will prove a real handful for any defence.
"He's a really direct player who I'm sure will quickly become a fan's favourite. He had offers from elsewhere, so it's especially pleasing that he chose to join us here in Inverness.
"He will join up with the rest of the lads at the end of the month and we still hope to add a few more players in advance of that."
Mulraney played for Crumlin United as a youth player, as well as Nottingham Forest, before joining QPR and also enjoying loan spells with Dagenham & Redbridge and Stevenage.