Gatdet, a senior SPLM-IO official, was separated with his family when he was illegally deported to Juba by Kenyan authorities in November 2016 following the collapse of a 2015 peace agreement three months earlier.
He was handed over to the National Security Service (NSS) who detained him on false charges for which he was eventually sentenced to death.
He would be released in November 2018, after exactly two years in jail and two months after the signing of the revitalized peace agreement which provided for the release of political detainees, among others.
In a statement, Gatdet announced the reunion with his family after travelling to Sweden on Thursday.
“Nice to have reunited with my family (kids) today in Sweden after exactly four years and two days,” Gatdet wrote. “[I] arrived today in Sweden. A great visit! There is time for everything.”