It was a long, twisting road to national recognition for Alfonso Thomas. A right-arm medium pacer from Cape Town, Thomas made his first-class debut for Western Province B in 1998-99, where he played a few matches until his move to North West in the 2000-01 season. He has represented Staffordshire and Somerset in county cricket, as a Kolpak player.

His lively pace and the capability to be a useful lower-order batsman earned him great appreciation. Thomas then moved to the Northerns Titans in 2003-04, where his brilliant haul of 36 wickets in eight matches of the Super Sport series exposed his potential as a bowler. Thereafter, he had a short but successful stint with South Africa A, which ultimately prompted the selectors to include him in the national side. In 2004, he was selected for the Test tour to India, as a stand-in for injured Andre Nel. But his international debut came only with the birth of the Twenty20 format, in 2007. Thomas later shifted to Dolphins for the 2007-08 season.

After a decent stint for Somerset in the 2009 Champions League T20, Thomas was signed for the IPL in 2011 by the newly formed franchise of the Pune Warriors India. The following year, the Titans signed him ahead of the 2012 Champions League T20.