The achievement, secured following Saturday's 0-0 draw with Montrose, marks the completion of stage one in the rebuilding process after liquidation resulted in the Ibrox club losing their SPL status and being demoted to Scotland's basement division in the summer.
Elgin City's win over Queen's Park saw Rangers crowned champions, with their nearest challengers no longer able to catch the Light Blues. McCulloch told the club's website: "There was obvious disappointment after the game, it didn't flow and we didn't play as well as we can. But to hear on the bus that we were champions was the best feeling in the world."
He added: "I've been lucky enough to win three titles before but I think this is my favourite one. I've been lucky enough to be captain for this one and it means the world to me and my family.
"We can only play against the teams we've been told to play against but, at the end of it, if you are giving me a winner's medal I am taking it. It really is a dream come true to captain the team and hopefully we can kick on now. This will definitely stay with me for the rest of my life - to captain a Rangers team to win a league means the world to me."
The goalless stalemate at Links Park was one of a number of disappointing results this season, as Rangers at times found the Third Division a tough league to negotiate. But 34-year-old McCulloch believes the experience can only be good for the youngsters who have been thrust into the top team this term.
He added: "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."
Ongoing debate over league reconstruction means a question mark still hangs over which division Rangers will be playing in next season.If proposals for a 12-12-18 structure are pushed through for the start of next season, they would remain in the bottom tier, albeit the time-frame for a potential return to the top division would remain the same.
It is a scenario manager Ally McCoist is strongly opposed to. He told Sky Sports News: "What I would like to happen would be promotion for our club having won the title. The players and the fans absolutely 100 per cent deserve that.
"It looks as though it will be SFL2 which is absolutely fine because the rules were made at the start of the season. In my opinion, you don't move the goalposts during the season in terms of promotion and relegation and things like that. We've won our championship and I would expect an actual progression which would be promotion into SFL2."
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