Callum Phillips, 49, from Dalbeattie, had denied killing Ryan Baird by causing an accident near Kilmarnock in October 2016.
Mr Baird, 39, was travelling to Glasgow with the Nith Valley Rangers supporters’ club to watch his team play Partick Thistle when the bus he was travelling on crashed into a lamp post.
The court heard the bus was ‘like a roller coaster’ shortly before the collision, hitting speeds of up to 73 mph. Mr Baird, from Sanquhar, died trapped in the wreckage, while others suffered series injuries, including a fractured pelvis, broken ribs and internal bleeding.
Phillips, a father-of-two, showed no emotion as the verdict was read out yesterday. Sentencing was deferred until next month.