The Take That star has created the Â£3m show, titled The Girls, with Tim Firth who wrote the 2003 Calendar Girls film.
They are both based on the true story of the Women's Institute members who stripped off for a charity calendar.
Barlow joined the cast and original Calendar Girls for the finale at the opening night at Leeds Grand Theatre.
He appeared at the curtain call to lead a performance of one of the musical's central songs, titled Yorkshire.
Singing the praises of the county has helped the show become a big hit with audiences in Leeds, although a bigger test of its success will come when it moves on from its home turf.
The only other confirmed dates so far are at The Lowry in Salford in January.
But with a budget of Â£3.4m and the backing of West End impresarios David Pugh and Dafydd Rogers, and 115-year-old Broadway theatre operator The Shubert Organization, there are bigger plans afoot.
National theatre critics were not invited to the first night in Leeds, perhaps in order to allow Barlow and Firth to continue to work on the show before risking it in front of influential reviewers.
Barlow may have been scarred by his first attempt at a stage musical earlier this year, when his music for the Broadway adaptation of Finding Neverland was described as "dull" by The Guardian and "fatally ersatz" by The New York Times.
The singer recently told BBC North West Tonight: "If you were to listen to critics in life you'd never do anything, so you should never listen to them."
The Yorkshire Post's theatre critic Nick Ahad was invited to see The Girls. He wrote: "It's a cliche to say that a show can make you laugh and cry, but The Girls does both in abundance...
"I'd bet my flat cap that this show will be booked into theatres in London and around the world."
Barlow's music, he wrote, "occasionally feels incidental, complementary to Firth's script as opposed to overpowering it". But he added: "When it does grab the attention, it really grabs the attention.
"This show... has an audience ready made: women of a certain age are the UK's biggest buyers of theatre tickets. When they buy tickets to see this, they will see their own lives reflected back at them."
The Girls revolves around lifelong friends Annie (played by double Olivier Award-winner Joanna Riding), whose husband is dying of cancer, and the hare-brained Chris (Claire Moore).
Chris hatches a plan to raise money by enlisting her fellow WI ladies to pose nude for a charity calendar.
The story of inspiring women who defy the pressures of age and appearance to shed their inhibitions as well as their clothes is likely to resonate widely, even if its Yorkshire roots hold less appeal in other locations.
Gary Barlow took to the stage in Leeds on Tuesday to open his new Calendar Girls musical, ahead of possible runs in the West End and on Broadway.