He attended the independent Solihull School (during which time he was also leader of the Birmingham Schools' Symphony Orchestra) and The University of Birmingham. Whilst at Birmingham he was a member of the student TV station, winning awards at NaSTA (National Student Television Association). By 1991 he was contributing to Sounds magazine.
Following this, Mzimba was one of the longest-serving presenters, a reporter and an assistant producer for CBBC's Newsround between 1998 and May 2008; second only to John Craven.
During his time as the presenter of Newsround, he appeared as himself on The Basil Brush Show episode Basil's Millions.