Freeth, who left If Only at the end of July, will help raise awareness of the brand, which was launched last September by Olly Lomas, and offer "strategic guidance"
Inspire My Holiday has already partnered with several popular brands, including Tui, One&Only Resorts, JA Resorts, Value Added Travel and Aurora Expeditions.
The platform helps brands promote trips based on destination and holiday experience, rather than price.
It expects unique visitors to the site to exceed 530,000 0over the next 12 months, with the team promising "numerous enhancements to the customer experience".
Lomas said Freeth would being a wealth of business development experience to the role, as well as "great energy".
Freeth added: “Olly and the team have got a great business, and I look forward to working with them to achieve their goals and continue to enhance the site.
"Olly’s passion, product knowledge and work ethic are exceptional, and I’m confident that together we can deliver web traffic to many more travel partners at a very reasonable cost."
Freeth’s appointment to the Inspire My Holiday board comes after he joined new field sales resourcing service Flexi Reps as non-executive director.