Barker studied Fine Arts at the Surrey Institute of Art & Design. She then did odd jobs in various areas including fashion, before settling into a career as an interior designer. An accomplished painter, she did up her flat in Battersea and was the subject of a House Beautiful magazine spread on interiors.
This led to work in television as a set designer, where she met her husband. It was at this time she was one of the group of people (including Laurence Llewelyn-Bowen) approached by the BBC in 1994 to work on a television show called Changing Rooms as one of the designers. During this time Barker also started co-presenting House Invaders in 1999, and co-presented a three-part special called Planet Christmas in 2001. After six years of Changing Rooms, restricted by the BBC's position on commercial endorsement and disappointed to be overlooked as a replacement presenter to Carol Smillie, she agreed to leave Changing Rooms.
Barker launched her more commercially focused career by accepting an invitation in 2002 to appear in the second series of the ITV1 show I'm a Celebrity... Get Me Out of Here!, on which she finished in third place on the final day, and became Queen of the Jungle.
Barker adopted a new personal image, being featured in lads' magazine shoots and making a yoga DVD. Commercially, she designed and advertised sofa for dfs and cabins for Thomson Holidays. She also brought out her own wallpaper range with Crown. She began presenting series for ITV, including With A Little Help From My Friends, Building the Dream and a daytime lifestyle series, Under Construction.
In 2007 Barker took part in the children's CBBC show Hider in the House, as the hidden celebrity.
Barker also appeared on a celebrity edition of Come Dine With Me, aired on 17 September 2008, alongside Peter Stringfellow, Michelle Heaton and Lee Ryan. Linda finished in joint first place with Ryan, both of whom scored 26 points.
Today Barker writes, publishes design books and writes a column for the weekend Daily Express magazine.
In 2009, Barker joined the design team on the ITV daytime series 60 Minute Makeover.