The 22-year-old returned for pre-season with his parent club following a stint at Rangers in the second half of last term.
However, King, who travelled to Estonia last week but didn’t make the match-day 18 for the second leg of the Europa League victory over FC Infonet, has been informed he is not part of the plans for the season ahead and is free to depart Tynecastle.
Inverness have made their move and the player will join Richie Foran’s team on loan for the upcoming campaign.
King’s contract with Hearts expires next summer, so his transfer to the Highlands would appear to signal an end to his time with his boyhood club.
The Portobello boy has scored 14 goals in 95 appearances for Hearts, although his game time diminished notably when the club returned to the Premiership last season.