Peter Williams, 62, knocked over Esmé Rose Weir in Cheshire in January 2016 as she rode a scooter on the pavement.
Mr Williams, of Poulton Road, Wallasey told the jury at Liverpool Crown Court that despite checking his mirrors he had not seen her as he mounted the pavement to park his van.
He said he had not driven since the incident and vowed never to again.
Mr Williams broke down in tears when the jury returned its not guilty verdict after three hours of deliberation.
Supporters of the girl's family also wept.
The jury heard Esmé and her mother Jessica Weir - who was pregnant - were heading to pre-school in Neston when the collision occurred.
Mrs Weir was walking just behind her daughter.
Mr Williams was delivering wood in a Ford Transit tipper van to a property on Gladstone Road.
"The van drove past me," said Mrs Weir. "I didn't think anything about it. Esmé was going ahead and the van came round into the gap and went up on the kerb. Esmé was slightly ahead of the van.
"I started to run because I realised what could happen. I dropped my bags and ran.
"I hit the back of the van. I saw the wheel hit the scooter at the back which made her fall and the wheel went right over her. I couldn't get there in time."
Mr Williams said he was driving at 10mph and saw a space big enough to park in.
He said he "slowed to a stop, indicated and checked my mirrors and drove on to the pavement. I heard a lady screaming and I got out the van to see what had happened and there was a little girl on the floor.
Mr Williams said he went to help her before she was taken to Arrowe Park Hospital where she later died.
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