Andrea Catherwood was born and raised in Belfast where her mother, Adrienne McGuill, was an announcer and newsreader at Ulster Television, from 1959 to 1969 and also presented The Romper Room from 1964 to 1969 as Miss Adrienne. Adrienne Catherwood was awarded an MBE in 2004 for her work with the charity Action Medical Research. Andrea was educated at Strathearn School in Belfast. Her broadcasting career began aged 16 when she joined the BBC in Belfast as a co-presenter of a youth current affairs programme, for which she won BBC Northern Ireland's Young Presenter of the Year award. The following year she co-presented the youth current affairs programme Up Front. Aged 18, Catherwood made a documentary for BBC Radio 4 about the 18 years of troubles in Northern Ireland.
Following an honours degree in Law from the University of Manchester, in 1990 Catherwood joined Ulster Television where she spent three years as a news and features reporter. In 1993 she joined NBC Asia in Hong Kong as a news reporter, covering the handover of Hong Kong to China and the 1997 stock-market turmoil. She travelled extensively throughout Asia, and in Burma interviewed opposition leader Aung San Suu Kyi.
She joined ITN in April 1998 starting as newscaster and senior reporter for ITV News, presenting the ITV Morning News and providing special reports for News at Ten. She then became medical correspondent for ITV News. Having joined Five News in 2000 as a main news presenter, she moved back to ITV in 2001.
In November 2001 she was the first British journalist into Mazari Sharif after the Northern Alliance captured the city from Taliban forces. She produced a number of reports, which received wide coverage in the British press. Catherwood was reporting from inside the prison at the beginning of the Taliban prisoners uprising when one exploded a concealed grenade that killed five people. Catherwood was injured in the knee by shrapnel.
In 2003, she was promoted and made the main anchor of the ITV Weekend News, plus a relief presenter on the ITV Lunchtime News and ITV Evening News.
Catherwood left ITV News in September 2006, to front The Sunday Edition, ITV's new political show with Andrew Rawnsley. However, this was quietly dropped in November 2007.
In 2006, she was scheduled to appear on the celebrity special of The X Factor: Battle of the Stars and to sing with James Hewitt but ITV management refused to give her permission to appear on the show. In 2007, she was a contestant on the ITV series Vernon Kay's Gameshow Marathon.
In July 2009, to coincide with the 40th anniversary of the NASA moon landings, ITN produced five special 10-minute programmes for ITV titled Mission to the Moon – News from 1969. Catherwood, a former ITN newscaster and correspondent, reported for these specials. The first aired at 22:35 on ITV on Wednesday 15 July and ran the following Thursday, Friday, Sunday and Monday.
In October 2009 Catherwood joined Bloomberg Television as part of the news station's relaunch, where she anchored Briefing, The Pulse, and Last Word. She left in March 2012.
Catherwood is now a weekly contributor to This Morning on ITV, as well as writing for The Mail on Sunday.
Over the past three years she has been a presenter on various Radio 4 programmes. She presented BBC Radio 4's Woman's Hour, as well as You and Yours, and is a regular stand-in presenter of the Media Show on Radio 4. In September 2017, she appeared on the BBC Radio 4 programme "Great Lives", nominating Constance Markievicz for a great life.
Catherwood married lawyer Gray Smith on 28 September 2002. The couple have three children, a son born in 2004 and twin sons born in 2005.