Janet Donaldson, who was appointed by the council in August 2009, was asked to leave her position although the reason behind her departure has not yet been made public.
A council spokesman confirmed that "a member of staff has been suspended", but refused to give further details.
Leader of the Conservative group in Calderdale Stephen Baines also said he was unable to comment on the detail surrounding Donaldson’s departure, but added that "everything is being done to ensure the children of Calderdale are safe".
Stuart Smith, who was Liverpool’s director for children, families and adults, and most recently acted as interim director of education and community in Wigan, has been drafted in to head up Calderdale’s children and young people’s services in place of Donaldson.
Calderdale is subject to a government improvement notice, which was imposed in April 2010 after an Ofsted report into the authority’s safeguarding and looked-after children services found the overall effectiveness of the department to be "inadequate".
A more recent report in February this year found there had been improvements in the department, but said areas for development included recording systems and management oversight.