Hamilton Ratshefola joined IBM as a graduate and trainee system engineer in 1990. He worked as a mainframe systems engineer in the banking and retail environment before moving into sales in 1993. He was promoted to management in 1995 and later moved to lead the Industry Team in Travel & Transportation in 1997.

Ratshefolawas then included in IBM’s development assignment programme, where he worked on assignment in the UK, Italy, Denmark and the US, to gain exposure to IBM client environments and global best case practice. Following this, Ratshefola returned to South Africa to lead the IBM Public Sector Business and worked with key government organisations, including SARS and the Department of Home Affairs, to solve their complex business problems.

In 2000, Ratshefolaco-founded Cornastone, a successful IBM Business Partner. He re-joined IBM South Africa in June 2013 as executive sales & development reporting to the county general manager. He is currently South Africa's Country General Manager, appointed in June 2015.