Al Aynsley-Green knows something about childhood hardship and bereavement.
Growing up in a Northumbrian mining community, he lost his father at the age of 10, and was raised by his "talented and inspirational" mother.
"At that time people did not acknowledge the needs of bereaved children," he said. "Actually, it is not too different for children who lose a parent through marriage break-up."
Professor Aynsley-Green, 61, is England's newly-appointed Children's Commissioner, and fighting to help young people has been his lifetime's work.
He has spent the past few months meeting young people on the streets, in schools, community centres and prisons, in his previous role as national clinical director for children at the Department of Health, and Nuffield professor of child health at London's Great Ormond Street hospital.
He was often shocked by what he saw.
"We are the fourth largest economy in the world. It is unacceptable that some children still endure those levels of deprivation. Some of the social turmoil is similar to what was happening in Victorian times. There is poverty, but there is also poverty of expectation."
He has studied extensively the social history of childhood.
"My role models are people such as Thomas Coram, Dr Barnado and Joseph Rowntree. Charles Dickens, of course, knew about poverty from his own experience. I have been looking at how and why they were successful pioneers in fighting for the rights of children."
In a 32-year career as a paediatric endocrinologist - a specialist in hormones - he has seen more than enough suffering.
"I understand about the pressures of adolescence. I know how to talk to children and help them through difficult times. What could be more devastating than having to tell a young girl that her condition means there is a likelihood she can never have a baby?"
He is fiercely opposed to smacking unruly children: "We are viewed with incredulity by other countries because we still allow it," he said, adding that he never raised a hand in anger to his own two daughters. For now, though, his priorities are to recruit a team to shape the commission. He will consult young people and other agencies shortly to establish which areas need his urgent attention.
"I have been in touch with the commissioners of Wales, Scotland and Northern Ireland and they have been very supportive and positive. I have much to learn from their experiences."
While his powers extend to interfering in their affairs, he believes this would be a "very silly thing to do".
He defends the legislation that created his post against criticism that he will be a government "poodle".
While his temporary office is at Caxton House, one of the Westminster buildings occupied by the Department for Education and Skills, he is anxious quickly to find an alternative.
"It is up to me, the staff I recruit, and the organisation we set up, to be as effective and independent as we can," he said. "Time will tell whether I am a poodle, or a house-trained Rottweiler."