Her first big break came in the late 1980s with a starring role in the long-running Granada Television comedy series Watching, in which she played a character called Pamela, opposite Emma Wray.Tarbuck then appeared as Angie in the 1988 Falklands War drama Tumbledown, which also starred Colin Firth, Paul Rhys and David Calder. In 2001, she took the title role in Linda Green, which ran for two series, ending in 2002.
In more recent times, she has guest starred on the Ricky Gervais comedy Extras, and has appeared in The Inspector Lynley Mysteries as DI Fiona Knight. In 2004, Tarbuck appeared in Series 6 of the long-running BBC One comedy French & Saunders, as a fictionalized version of herself, where she had the role of Producer for "Saunders & French Productions" with Christopher Hague-Moody. In 2005, Tarbuck appeared as Mrs. Jellyby in the BBC One serial Bleak House., and in 2006 she appeared in episode six of the sitcom Saxondale, as a full-figured rock chick.
In 2009 Tarbuck starred as Staff Nurse Tina in her first role in a feature film, in The Be All and End All.
After a seven-year break from television, she presented the fashion programme She's Gotta Have It in 1998. Her exuberance, humour and presenting skills landed her a presenting job on The Big Breakfast where she forged a successful partnership with Johnny Vaughan.In 2001, she teamed up with her father for a celebrity edition of Who Wants to Be a Millionaire? In the early 2000s, she hosted the Sky One game show Blockbusters and has been a guest presenter on Have I Got News for You. In 2003, Tarbuck hosted Channel 4's Emmy Award winning panel-discussion/gameshow Without Prejudice?.
She has also presented a one-off quiz for Five called I Blame The Spice Girls to celebrate Five's tenth birthday. She has also been one celebrity to appear in a series of adverts for the UK supermarket Asda.
During September 2007 she co-presented the weekday afternoon show on BBC Radio 2 with Mark Radcliffe, whilst Steve Wright was on leave. In December 2007 (and again in January and March 2008), she once more hosted the show, this time as a solo presenter. In July 2008 she once again co-presented with Radcliffe. In December 2008 and January 2009 she presented the Saturday morning slot on BBC Radio 2 with Martin Freeman. For a week in March 2009 Liza stood in for Sarah Kennedy's popular Dawn Patrol show. In August 2009, she stood in for Jonathan Ross on his Saturday morning show on Radio 2; alongside her on the show was Huey Morgan of Fun Lovin' Criminals. The pair presented the show again in November 2009.
In July/August 2010, Tarbuck stood in for Simon Mayo on his BBC Radio 2 Drivetime Show for three weeks. She stood in for him again from April 18–22 in 2011, from August 1–19 in 2011 and February 14–18 in 2012.
In March 2012 the BBC announced that Tarbuck would start presenting her new Saturday night show on BBC Radio 2 from 12 May 2012. It will be on between 6 and 8pm, and replaces the programme presented by Alan Carr and Melanie Sykes after Carr announced his decision to leave the network.