Lord Justice Stuart-Smith said the sentence on Melvin Sollors, 47, of Tamworth, Warwickshire, was 'manifestly too long'. Sollors was released, having already served nine days in prison.
The attack followed the conviction of Jeffrey Williams, 23, who was charged in Warwick Crown Court on 24 May with hitting Christian Sollors, Sollors's son, with an iron bar.
Sollors was angered by the sentence of 150 hours' community service given to Williams and told police he 'saw red' when the defendant laughed in court.
He shouted abuse from the public gallery and later punched Williams and kicked him when he was on the ground. Sollors refused to apologise when brought back in front of Judge Richard Cole.Reuse content