The 22-year-old right-back has previously played for Sundowns' reserves, Tshakhuma Tsha Madzhivhandila and most recently Royal Eagles.
Mamelodi-born Sambo, who has also represented Amajita, has signed a two-year deal with Ea Lla Koto.
"He's a former Sundowns and national under-20 and under-23 player, he has signed a two-year deal with Free State Stars," the player's representative Godfrey Mushanganyisi confirms to snl24.com/kickoff.
"He was playing for Royal Eagles this season, so he did not sign the two-month extension. Free State Stars gave him a pre-contract, which commenced as of 1 September 2020."
The Bethlehem-based side finished fifth in the GladAfrica Championship this season and missed out on the promotion playoffs, while Eagles were relegated to the ABC Motsepe League.
In other related news, former Jomo Cosmos and Eagles player Tumi Ngwepe is asking for financial donations to enable him to attend overseas trials.
The 25-year-old is hoping to go for a three-month trial with Estudiantes de Medellin FC of Colombia, according to Mushanganyisi, but will need to raise R12 000 for a plane ticket in order to qualify for a travel Visa.