News of the high-profile investment follows the recent announcement of a further funding round for My1Login, which raised £1.3 million from a consortium of private and public sector investors.
The firm was set up in 2007 to help tackle the issue of employee passwords after seeing corporate data breaches.
Williams said: “It’s been fantastic to see My1Login grow and gain so much traction with large enterprise customers. I can see the same passion and dedication in the guys at My1Login that I saw in my own team.
“My1Login are perfectly placed to be the European leader in identity and access management and I’m excited to be involved in the next stage of their growth.”
Skyscanner is one of only two technology companies in Scotland to be ranked as a “unicorn” – meaning it is valued in excess of $1 billion.
Mike Newman, chief executive of My1Login, said: “I have long admired Skyscanner as a company and Gareth as a role model for building a hugely-successful global technology business.
“We feel honoured to attract investment from the co-founder of one of Scotland’s unicorn companies.”
My1Login, which has more than 1,000 clients on its books, recently announced that Scottish Water’s Business Stream spin-out had become a major enterprise customer.