40 year old Gavin Garraway was stabbed through his car window in March last year near Clapham Common Tube station.
20 year old Zion Chiata, from Wandsworth, has been handed a minimum of 21 years in prison for Mr Garraway's murder.
22 year old Tishaun Panton was also sentenced to ten-and-a-half years for manslaughter.
Mr Garraway's car was pursued by Chiata, who spotted him driving with his brother who was linked to a rival gang.