Vishnu was appointed to the board on 8 May 2013. He was executive head: joint ventures and exit operations of Anglo American Platinum Limited, a position he retired from on 31 December 2018. Before joining Anglo American Platinum in 2011, he was executive vice-president and head of South African operations for Gold Fields Limited and, prior to that, vice-president and head of operations at Driefontein Gold Mine.

His 35-year mining career was shared between Gold Fields Limited and Anglo American Platinum. It was briefly interposed with a two-year period in 2004 with the Council for Scientific and Industrial Research in South Africa, where he was director of mining technology and group executive for institutional planning and operations.

Vishnu also previously served on the Board of Foskor Proprietary Limited as an Independent Non-Executive Director.