Silverton was born in Waltham Abbey in Essex, England, the daughter of English parents; Terry Silverton, a black-cab driver turned registered hypnotherapist and Patricia Silverton, who now heads her daughter's company. Silverton has two sisters, Claire and Amy. Silverton attended West Hatch High School in Chigwell, Essex, where she was a champion swimmer and started to compete in the triathlon. She was a Girl Guide and gained the Queen's Guide Award. She spent a year studying Arabic and Middle Eastern politics before switching to psychology and graduated from Durham University where she attended St. Cuthbert's Society.Kate went to Zimbabwe with Raleigh International, spending her gap year working for them in Egypt and Lebanon.
From 2005 until December 2007, she was the presenter from 08:30-11:00 on BBC News 24 along with colleague Simon McCoy, although she was frequently absent as she was also a regular relief presenter for BBC Breakfast, presenting during some of Sian Williams's maternity leave.
In December 2007, Silverton was named as the presenter of the BBC News (8 p.m. summary) - a 90-second round up of the news shown on BBC One, which she presented for two months. She presented the BBC News at One from February to August 2008, whilst main presenter Sophie Raworth was on maternity leave.
In January 2009, Silverton began to present the BBC Weekend News Late Bulletin as a regular presenter. From Monday 23 February 2009, Silverton presented BBC Breakfast with Bill Turnbull, again covering for Sian Williams's maternity leave, which ended on 31 August 2009. During September 2009, she presented and reported for BBC News from Lashkar Gah, Afghanistan.
She presented her final news programme on 3 October 2011 before taking maternity leave and returned to the News at One on 2 April 2012. Until May 2012, she was the deputy presenter of the BBC News at One, presenting on Mondays and when main presenter Sophie Raworth was unavailable. Silverton remains the main relief presenter of the programme on Thursdays as well as BBC News at Ten" on Saturdays, but has lost the deputy role to Sian Williams after Williams left BBC Breakfast prior to that programme's relocation to Salford. She occasionally presents on the BBC News Channel and on BBC world news's GMT program.
On 1 April 2008, alongside the historian Dan Snow, she presented live coverage of the celebrations held at RAF Fairford for the 90th Birthday of the Royal Air Force. On 24 August 2008, Silverton presented live coverage of the celebrations of London becoming the 2012 Olympic Games host city, from The Mall. She presented New Year Live aboard HMS Belfast in London on 31 December 2008 on BBC1 with Nick Knowles.
She has appeared as a newsreader on the BBC drama Spooks.
In May 2009, she presented a documentary called 10 Things You Need to Know About Sleep, which looked at different ways to deal with insomnia.
From January 2010, she presented the Sunday morning show on BBC Radio 5 Live, running from 09:30 to 11:00. The show's format was revamped as part of a general review of the schedules in January 2010.
Silverton married Mike Heron at Fleet Street's St Bride's Church on Saturday 18 December 2010. On 5 November 2011, Silverton gave birth to a baby girl named Clemency Florence Rose Heron at Queen Charlotte's Hospital, London. On a BBC Radio 4 programme (broadcast on 2 May 2013), Silverton stated that her daughter had been conceived "naturally" after four unsuccessful cycles of IVF.
In January 2008, Silverton sued a clinic after an allegedly botched cosmetic surgery procedure to remove acne scars.