Harvey is possibly best known for her starring role as Jan Howard in the British TV drama Howards' Way, from 1985–90, in which she ran a fashion boutique named Periplus. The boutique specialised in the sale of après sail wear (and was also the first UK headquarters of the German mail order franchise, Die Spitz). Subsequently a partnership, Howard Brooke, was formed which ran multiple boutiques as well as producing its own designs. There followed the launch of an internationally renowned couture house (with attendant fragrance and cosmetics lines), the House of Howard, which was successfully floated on the stock exchange.

During the 1990s, Harvey appeared in the action series Bugs, and more recently was a regular cast member in the Five soap opera Family Affairs (in which she played Babs Woods). She has also guest starred in many other high profile British dramas including A Touch of Frost, Inspector Morse and Lovejoy.

Harvey starred in the 2010 UK tour of Calendar Girls and is set to appear in a second run of the show in late 2011.

From March 2015 to July 2016, Harvey was appearing in the BBC soap opera, EastEnders, as Margaret Midhurst, the family solicitor, and aunt, of Sharon Watts (Letitia Dean). Her character was sensationally killed-off when her on-screen brother, Gavin Sullivan (Paul Nicholas), pushed her over a balcony during a scuffle.