Speaking at the National Children and Adult Services Conference in Liverpool, Maggie Atkinson said local authorities should welcome government proposals to strengthen children's trusts.
She said: "We're five years into Every Child Matters. We now need to establish what the core functions of every children's trust are."
Atkinson also told colleagues to prioritise joint working and "silence chatter" from staff who claim the integrated working agenda is threatening professional specialism.
She warned that "a modern view of leadership across the system" was needed to improve the life chances of children.
She added that joint working is real in a growing number of places, but said the ADCS and the Association of Directors of Adult Social Services are engaged in discussions to explore how to integrate workforces further.
