Surrey CC director of children's services, Dave Hill, died suddenly last night, the council has announced.
The former president of the Association of Directors of Children's Services (ADCS), Mr Hill joined the council in 2018 from Essex CC and was responsible the rapid improvement of the council's children.
Surrey chief executive, Joanna Killian, said: ‘Dave was an amazing colleague and great friend.'
‘At the heart of it he was just a great guy whose passion in life was his family – wife Jo, and daughters Laurel and Lydia whom he adored – and doing the very best he could for vulnerable children.
‘My heart goes out to his family and to all his colleagues and staff who I know will be as devastated as I am that we have lost this amazing, talented man.'
She attributed the turnaround in the council's children's services to Mr Hill's ‘inspirational leadership, sheer energy and drive'.
Council leader, Tim Oliver, said he was devastated at the news.
‘Dave was a tower of a man who was held both in respect and affection by those who worked with him at Surrey and across the whole of children's services.
‘He was thoughtful, inspirational, committed and self-deprecating. He will be irreplaceable.
Mr Hill spent eight years as director of children's services at Essex, and previously held the same post in both Croydon and Merton LBCs.
He began his career in a Southwark LBC children's home before training as a social working and working across five London boroughs.
In 2018 he was awarded a CBE for services to children's social care and served as ADCS president in 2015-16, and as a Government-appointed commission in Norfolk and Birmingham.
Essex CC chief executive Gavin Jones said: 'Dave will be remembered for his enthusiasm and for the leadership and support he gave to his colleagues. His presence and strength of personality, and his commitment and passion for everything connected with children's services, adult social care and education will be greatly missed.
'Dave was well respected, incredibly popular and there will be many employees at the council who will be saddened by today's news but will have very fond memories of working with him.'