Terry Butcher's team have strung together an incredible 19-match unbeaten run to become only the second team in SPL history - after Dunfermline a decade ago - to bounce back at the first attempt.
Inverness' longest-serving player and record appearance holder Ross Tokely told BBC Radio Scotland: "I'm absolutely delighted.
"To get back in the SPL after a year is an amazing achievement.
"I've won the First Division before but I have to say, the challenge we had this year, this is the best feeling I've had at the club."
Tokely, who has been at the club for 14 years and has played for them in all four divisions, added: "Everybody wrote us off at the start of the season and it did take a while to get going.
"The team has bonded well and grown every week."