Sullivan was best known for creating the Sullivan Principles, a set of ethical guidelines later signed by officials from more than 125 US corporations working in South Africa. The principles pledged the corporations to practice racial non-discrimination in their South African operations and to opposing apartheid.

The principles enshrined a set of corporate practices that boldly challenged the apartheid system then in force by calling for racial desegregation in the workplace—including in cafeterias and toilets—equal pay for equal work, the promotion of more non-whites to better positions, and improved housing, schooling, recreation and health facilities for workers.

But while the Sullivan Principles, drafted in 1977, were hailed at the time by many people defending human rights, Sullivan eventually abandoned them as not going far enough, saying the white South African government of the time was not doing enough to end apartheid.

In the 1980s, he called on corporations to pull out of South Africa and pushed for US sanctions against the country, according to the International Herald Tribune.

"There is no greater moral issue in the world today than apartheid," Sullivan said in 1987. "Apartheid is against the will of God and humanity."

Indeed, there were those in the anti-apartheid movement—including church activists—who said the Sullivan Principles were too little, ...