MacAskill leaves Scotland on Sunday, where she was associate editor for magazines, to return to Express Newspapers, where she worked as group fashion director until early 2004.
She began her career in book publishing before moving on to edit a wedding magazine. In 1996, she became deputy editor for the launch of Spectrum for Scotland on Sunday, and joined the Express in 1998, initially as deputy fashion editor.
She said: "I am delighted to be given the opportunity to launch this new shopping concept magazine. I have a brilliant team in place who will be working hard with me to make Happy a success."
Northern & Shell appointed a former editor of Tatler, Jane Procter, as consultant editor of Happy in October.
Billed as an upmarket women's shopping title, Happy will be supported by a multimillion-pound TV campaign.
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