Ms Smith, who is currently director of UK children's services for Barnardo's, will head the Early Years Directorate, dubbed oftot, from March. The pound;85,000 appointment has been welcomed by under-fives organisations, who said Ms Smith was committed to children's issues.
The 53-year-old, who trained as a nurse, was one of a handful of lone parents who founded a community nursery scheme in Keighley, West Yorkshire. It was the district's first modern childcare facility.
She was re-cruited by Gingerbread, the single parents network, and then workd in local government. After a couple of years in higher education, she joined the children's charity Barnardo's in 1998, overseeing 3,000 staff and 15,000 volunteers.
In her new role she will be working with 1,600 staff in eight regions in England, including about 1,000 home-based childcare inspectors.
From September, the inspectorate will be responsible for the regulation and inspection of 84,000 childminders, 25,000 nurseries, playgroups, cr ches and out-of-school clubs, and 10,000 holiday schemes.
Eva Lloyd, head of the National Early Years Network, said: "Maggie has substantial management experience. She is also well aware of the concerns of statutory and voluntary childcare providers."