CYP Now has learned that ADCS president Debbie Jones, who is director of children's services in Lambeth, will take on the role from September.
Only last month Ofsted announced that Jones would join as London regional director for education, learning and skills.
Goldup joined Ofsted in September 2009 as director of social care development, before being appointed deputy chief inspector in January 2012.
An Ofsted spokeswoman confirmed that Goldup will leave "by mutual agreement" at the end of March 2013.
“In his three and a half years with Ofsted, John has reformed social care regulation and inspection, and has firmly established Ofsted as a powerful force for improvement in social care services for children," the inspectorate said in a statement.
“Having led a step change in this area of Ofsted’s work, John has concluded that it is time to take his career in a different direction.
"He has agreed with the Ofsted board that this is the right moment to leave the organisation, and the board and his colleagues wish him every success as he moves on to face new and different challenges.
"Debbie Jones will take over on the national lead for social care when she joins Ofsted as regional director, London, on 1 September 2013. In the interim Sally Rowe will be acting national director, social care, as well as regional director for the north west."