She has also been a consultant at the financial services company KPMG and theatre manager at the Half Moon Theatre in east London. She is a director of the social lender Big Society Capital and a trustee at Historic Royal Palaces, the charity that looks after buildings including the Tower of London and Hampton Court Palace.
She will join the BLF in the autumn and takes over from Peter Wanless, who leaves at the end of this month to become chief executive of the NSPCC.
Ceri Doyle, the BLF’s director of strategy, performance and learning, will be acting chief executive during the intervening period.
Peter Ainsworth, chair of the BLF, said in a statement that Austwick was joining the fund at "an exciting but also challenging time".
"We are operating in a difficult economic climate where the delivery of our mission, to support people and communities most in need, is ever more pressing," he said.
In a statement, Austwick said she was "relishing the opportunity to build on the fund’s impact to date in ways that bring lasting benefits to communities and quality of life throughout the UK".