Leon is also a contracted columnist to Arena Holdings Ltd, with his columns appearing weekly or monthly in Business Day, Sunday Times, and BusinessLive.

From 1990 to 1994 he chaired the DP's Bill of Rights Commission, and as such was an advisor to the Convention for a Democratic South Africa (CODESA) and a delegate to the multi-party negotiations that led to the end of apartheid and the establishment of a non-racial democracy in 1994.

Leon built a high media profile as an opposition leader by criticising the ANC government under Nelson Mandela but more so under his successor, President Thabo Mbeki.

[11][12] On 29 November 2007, Mr. Leon was a guest at the prestigious Yale Political Union, keynoting a student debate on the topic "Resolved: The Nation Should Not Be Tied To Ethnicity."

The book was favourably received, The Economist describing it as "eloquent, funny and rich... an important record of South Africa’s young democracy, witnessed from the other side of the fence".

[16] In the last quarter of 2008, Leon was a visiting fellow at the Cato Institute Center for Liberty and Global Prosperity in Washington DC.

[17] Leon published a series of articles in Business Day from the campaign trail of the 2009 South African general election.

[18] After Leon completed his over 20 years as an MP, he was invited to write two weekly columns in leading South African Sunday paper Sunday Times and in leading daily paper Business Day, winning excellent reviews for his writing and analysis even from previous political opponents.

Leon followed many DA and Democratic Party members who became ambassadors, such as Harry Schwarz, Zach de Beer, Douglas Gibson and Sandra Botha.

Leon also published a memoir of his ambassadorial life titled The Accidental Ambassador: From Parliament to Patagonia (Pan MacMillan, 2013).

The book received critical acclaim with Business Day, where it was said to be "fascinating... Leon is an excellent writer and recounter... eloquent and heartwarming."

Sue Grant-Marshall in Business Day wrote: "It is no surprise that in the year after Mandela's death a cascade of books by those who know the international icon are flooding the shops and bookshelves.

"[21] In March 2021, Jonathan Ball Publishers released Tony Leon's latest book: Future Tense - Reflections on My Troubled Land.