The 20-year-old is the second summer recruit for new manager Richie Foran.
A Republic of Ireland Under-21 international, Mulraney was on loan at Dagenham and Redbridge and Stevenage Town last season.
"He has plenty of pace and will prove a real handful for any defence," Foran told the club website.
"He's a really direct player, who I'm sure will quickly become a fans 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."
Inverness Caledonian Thistle have signed Jake Mulraney on a two-year deal following the winger's release from Queens Park Rangers.