Ackerman has four Test appearances for South Africa all made in 1998. He made a gutsy 57 in his first Test innings but after that made little impact. It was thought that Ackerman had a weakness against top class spin as Mushtaq Ahmed and Muttiah Muralitharan were particularly successful against him in successive series.
He joined Leicestershire in 2005 under the Kolpak ruling which allowed him to play for an English county without being registered as an overseas player. He was the captain of Leicestershire in 2005, having some success in one-day cricket.
In the 2006 season, Ackerman stepped down to concentrate on his batting. This move seems to have paid off as Ackerman scored 309 not out against Glamorgan at Sophia Gardens, the highest ever first-class score by a Leicestershire player.