David Crawford, 59, died from multiple injuries after being mown down by the van on the A38 in Plymouth in May.
Benjamin Parry, 42, of Devonport, Plymouth, was found not guilty of murder but was convicted of manslaughter at Plymouth Crown Court.
The jury is yet to reach a verdict on charges against two other men – Chad Brading, 36, and Thomas Pawley, 32.
Mr Brading, from Plymouth, and Mr Pawley, of Ivybridge, both denied murdering Mr Crawford.
Parry had also denied murdering Mr Crawford but towards the end of the trial he admitted manslaughter and was convicted of that charge. He will be sentenced at a later date.
The judge advised the jury they could no longer consider murder charges against Mr Brading and Mr Pawley and would need to reconvene to consider their verdict regarding the lesser charge of manslaughter.
The case continues.