Only months after the scandal surrounding the 2002 Salt Lake City Olympic winter Games broke, Tewksbury became prominent around the world as a critic of the IOC and demanded reforms to the system.

"[9][10] Tewksbury was also highly critical of Swimming Canada's organization in the wake of the national team's poor performance at the 2004 Summer Olympics in Athens, where they failed to medal.

He was a panelist at the 2003 National Gay and Lesbian Athletics Conference in Cambridge, Massachusetts, on a panel of LGBT Olympians that also included rower Harriet Metcalf and high jumper Brian Marshall.

[9] Tewksbury remains a public figure working as a motivational speaker, a television commentator for swimming events, and a continued activist.

On November 30, 2006 Tewksbury was the Master of Ceremonies for the Tribute to former Prime Minister Paul Martin at the Liberal Party of Canada's Leadership and Biennial Convention in Montreal.

During the 2008 Summer Olympics, Tewksbury served as CBC Sports' swimming analyst alongside play-by play announcer Steve Armitage.

In December 2008 Tewksbury was invited by the government of France to speak at the United Nations in New York City on the day that a declaration was introduced that affirms gay rights and seeks to decriminalize homosexuality.

On July 23, 2015, Tewksbury presented his gold medal to the Canadian Museum for Human Rights in Winnipeg for an exhibit promoting the power of sport to influence positive change.

[16] In May 2019, Tewksbury performed an autobiographical one-man show called Belong, which was produced by Wordfest and staged at the DJD Dance Centre in Calgary.