Lu Qing, who lives in southern China's Guangdong province, posted pictures of her grandfather dressed in an array of pink skirts, red tights and fur-lined women's jackets to promote her online fashion outlet Yuekou.
The images of Liu Xianping have since gone viral and seen him branded the "world's coolest" grandfather by Internet users for his slender legs and modelling poise. They have also boosted his granddaughter's bottom line.
"Since the pictures came out, we've had a huge number of website visitors, and are selling five times as many clothes as before," Lu says.
"Previously, we sometimes sold less than 10 items a day, and were feeling depressed about the business."
Lu says her grandfather was "surprised" by the reaction to the photos and at least three other stores had asked him to pose for them, but he was unlikely to accept.
"He doesn't see modelling as a way of making money, its just about having fun with his relatives," she said, adding she hopes to use his services again.
She says her grandfather has "a young heart" and enjoys visits to parks and zoos, as well as playing games on his mobile phone.
"He thinks bringing people's attention to the elderly is great, so he's been very happy recently," she says.
The Offbeat China website, which tracks Internet developments in the country, says Liu's modelling illustrates the transformation it has undergone.
"It is stories like this when one can get a sense of what a diversified society China has changed into in the past 40 years, especially for someone like Liu who has lived through one of the most rigid times in China's history," said a post on the site.
Lu says Liu, who has worked as a teacher and a farmer, did not need prompting to take up modelling.
"My grandfather saw some new stock one day and thought some of the colours were pretty... he wasn't embarrassed to model because we're all very close to him," she says.
She adds that his favourite item was a red women's coat.