A gazette notification issued by the Ministry of Public Administration on Monday confirmed the appointment, cancelling his post-retirement leave (PRL).
With the new appointment, PSC now has 11 members.
Sadiq, who served as the secretary to the Election Commission and as the education secretary, went on PRL on Sept 18 this year.
A member of the Bangladesh Civil Service’s 1982 batch, he was born in Sunamganj.