His conviction for causing an environmental disaster was not only ironic but also marked a dramatic fall from grace for the man once hailed as the "Swiss Bill Gates."
The descendant of a Swiss industrialist dynasty, Schmidheiny was a young law graduate when in 1976 he took over the reins of the family business called Eternit specialising in building materials -- among them asbestos-reinforced cement.
By the mid-1980s he had diversified into other ventures, investing in forestry firm Grupo Nueva and other multinationals.
Schmidheiny was notably credited with helping revive the Swiss watch industry with a joint venture to assume control of ASUAG-SSIH, which later became Swatch Group.
His business acumen saw him elected to the board of directors of some of Switzerland's household names, among them the Union Bank of Switzerland (later UBS) and food giant Nestle.
In the 1990s he turned his attention to charity and to the environment, and was even appointed advisor to the secretary general of the United Nations Conference on Environment and Development ahead of the 1992 Rio Earth Summit.
He went on to establish the Avina foundation promoting social and ecological sustainability, followed several years later by a sister foundation in Latin America.
"As a businessman, I tried to create social and economic prosperity and, at the same time, to protect and regenerate the environment," he wrote on his website, www.stephanschmidheiny.org.
"As a philanthropist, my desire was to spur positive social change and safeguard opportunities, as best I could, for future generations."
In 2009, Forbes magazine titled an article on Schmidheiny "The Bill Gates of Switzerland," a reference to his membership of an elite club of donors, including Gates and Warren Buffet, who have given away $1 billion or more.
Last year the publication estimated Schmidheiny's wealth at $2.9 billion.
He began retiring from his business activities in 2001 however and now lives in Costa Rica, according to Swiss news agency ATS.
Schmidheiny's co-defendant, wealthy Belgian baron Jean-Louis Marie Ghislain de Cartier de Marchienne, has kept a much lower profile throughout his 90 years.
His links with Eternit go back to 1950 when he married Viviane Emsens, a descendant of Alphonse Emsens, an industrialist and founder of Eternit Belgium, which later became Etex.
After the marriage he became a key figure in the group, heading up several of its divisions.
A rare portrait by economic magazine Trends in 1995 revealed that De Cartier de Marchienne is himself of aristocratic stock dating to the 15th century.
On his mother's side he is linked to the publishing industry in Flanders and notably ran one of the world's biggest producers of playing cards, Carta Mundi.