A graduate of the Australian National University (BA, politics and history), University of Sydney (BEc) and the Australian Graduate School of Management (MBA), Wallace's publications include Greer, Untamed Shrew (Pan Macmillan, 1997; Faber and Faber, 1999) and The Private Don (Allen & Unwin, 2004).

Wallace is a member of the Canberra Press Gallery and has worked for a wide range of print and electronic media outlets there including The Australian, The Australian Financial Review, Business Review Weekly and ABC Television. She is a regular member of judging panels for the Walkley Awards for Excellence in Journalism each year. Wallace can be heard on regular radio spots with 666 ABC Canberra and breakfast on Adelaide's top rating talk station 5AA.

During the 1980's Wallace was a political advisor to Peter Shack MP, a Western Australian Federal Liberal Member of Parliament. She served in this role for many years.

During the 1990s Wallace's articles in the The Australian Financial Review were very critical of Dr John Hewson, then leader of the opposition Liberal Party and whose radical right-wing programme, "Fightback!", anticipated the political agenda of the Howard Government. She claims that her biography of Hewson and her influence contributed to his political demise. Later she broke the story that she also claims sparked the resignation of Liberal Party leader Alexander Downer, allowing John Howard to regain the post and later become Prime Minister.

Recent journal articles include Libertarian Nation By Stealth (Griffith Review, 16, 2007) and Clean, Orderly and Laminex Coloured (Griffith Review, 19, 2008). Wallace is currently working on a biography of Prime Minister, Julia Gillard.