"What is it like to be a child or a young person today in England, the fourth richest country in the world?" he asks.
His role was created as part of the Every Child Matters agenda, a drive to put children's interests at the centre of all children's services and to join up the thinking in education, health and social services.
His own background is in health - he was previously national clinical director for children at the Department of Health.
Professor Aynsley-Green likes to present statistics and research in the real world. Speaking at a children's services network conference recently, he began his speech by showing a photograph of one of his five grandchildren.
And he asked: "Are we investing enough in the earliest stages of attachment between carer and child? Do we as a community care enough about children other than our own? Where do we ever talk about love in policies or practice?"
He has identified eight themes that his office will tackle: children and young people in society, bullying, antisocial behaviour, immigration, disability, vulnerable children and young people, minority groups and health and wellbeing.
His own experiences lend him empathy with the children he is championing.
"My father died when I was 10 and I was left rudderless to navigate adolescence without him. The denial of the importance of fatherhood is something I feel very strongly about," he said.
"I was bullied. I was born in Northumberland and my family moved to London when I was 10. I was bullied because of my accent. It only got better when I changed school. But I lost the accent as fast as possible."
He is against the demonisation of children as yobs. He wants children's achievements to be celebrated. He wants children to be valued as individuals. And he wears hoodies.
He has already tackled the issue of pain relief (40 per cent of children attending accident and emergency departments with broken bones are offered no pain relief) and his office's first publication is a booklet of children's stories about bullying, antisocial behaviour and asylum.
Contact the Office of the children's commissioner on 0207 273 5559