The Ibrox outfit were crowned champions despite drawing 0-0 with Montrose on Saturday after Queen's Park lost 1-0 to Elgin City to fall 22 points behind.
The title was warmly welcomed by skipper McCulloch and feels it will spur the 'Gers players on to bigger and better things after copping plenty of criticism throughout the campaign.
"There was obvious disappointment after the Montrose game. It didn't flow and we didn't play as well as we can," he said.
"But to come home and hear on the bus that we were champions is the best feeling in the world.
"I think it's a good thing that they take a bit of criticism.
"I think the low points this season, the hard times, have made the boys stronger for next season. That's the way I look at it anyway.
"We're just happy to be where we are with five games left and the number of points we are ahead. You could say it's been easy but it's been far from that.
"The boys are just delighted and the coaching staff are as well."