De Leon was born in Manila in 1977. She and her family moved to Australia in 1978. She is the oldest of three daughters; her two younger sisters were born in Australia. The family spent most of de Leon's childhood in Sydney.
On 30 April 2000, when de Leon was 22 years old, she met her future husband Daniel Jones. At the time, Jones was a member of the Australian pop band Savage Garden. The couple met at the 42nd Annual TV Week Logie Awards.
In 2003, after over three years of dating, Jones proposed to de Leon during his 30th birthday party at the GPO Bar in Brisbane. Over one hundred attendees—including Jones' parents—were "shocked" by the surprise proposal.
On 9 October 2005, de Leon and Jones married at Avica Weddings and Resort on the Gold Coast in Queensland. De Leon's wedding dress was designed by Bora of 'Bora Couture while one of de Leon's friends designed a pearl set for the back of the gown and diamond pieces for the front. Jones wrote a song titled Love Is Enough for his bride.
On 25 February 2006, Kathleen confirmed that she was four months pregnant. The couple's first child, daughter Mikayla de Leon Jones, was born on 26 July 2006. On 30 October 2010, de Leon gave birth to the couple's second child, Keira.
De Leon started singing and dancing at an early age. She taught herself to play the guitar, prompting her parents to enroll her in The McDonald College, an exclusive performing arts school in Sydney, Australia. She was awarded both the Roberta Armstrong and Kelloggs Scholarships to study at the school, where she studied dance, drama, and voice for a number of years while making professional auditions in her spare time.
De Leon also trained with the Australian College of Entertainment in Castle Hill, New South Wales. She also competed in the Australian television talent show New Faces —where she came third in the grand final— and appeared on various Australian television shows, including Heartbreak High, Ridgey Didge, Swap Shop, and the At Home Show with John Mangos.
It was while she was performing at a fundraiser for The McDonald College that de Leon was discovered by one of the directors for the Cameron Macintosh company. She appeared in two musicals in Australia mounted by the Macintosh company, Miss Saigon and Rent. She stayed with the cast of Rent (where she was an understudy for the role of Mimi) and was dance captain for the musical, until being cast in Hi-5 in 1999.
Departure from Hi-5Edit
In July 2007, it was announced that de Leon was leaving Hi-5 permanently to focus on raising her child and family. De Leon stated that she was still interested in working on television, but only if an opportunity existed in her then-home of Sydney so she could remain close to her family. De Leon was the first of all the original members to permanently leave Hi-5.
Kathleen de Leon Jones currently resides in Las Vegas with husband Daniel and daughters Mikayla and Keira.