The Olympic bronze medallist joins sport stars including Sir Chris Hoy, Jessica Ennis-Hill and Rebecca Adlington in promoting the Glasgow Games, which begin in July.
The 19-year-old represented Great Britain at the Beijing Olympics aged just 14 and won two Commonwealth gold medals in the synchronised and individual diving competitions at the 2010 Commonwealth Games in Delhi.
Daley will meet fans in Glasgow this Sunday at an event to encourage young people to become involved in the Games.
He said: "I'm really looking forward to seeing Glasgow and be a part of the countdown to the Commonwealth Games. I want everyone to get behind the Games and all the athletes. It'll be fun but tough.
"I have great memories of winning Gold in Delhi, so I'm totally focused on training and holding on to my title."
Glasgow 2014 chief executive David Grevemberg said: "Tom's the perfect ambassador to inspire young people and help us get everyone involved in the UK's next major sporting celebration.
"We are delighted to welcome him as an official ambassador for the Games and look forward to introducing him to Glasgow this weekend, and working with him over the next year to deliver the friendliest of family-friendly Games."
People can apply for Games tickets for the 17 Commonwealth sports until September 16. Prices start at £15 and more than two-thirds of the tickets cost £25 or less.
Demand for tickets to see the most popular sports is already outstripping supply, organisers have said.