The Colombian recently returned to South Africa from a visit home, and is eager to repay the faith shown in him by the Glamour Boys.
“This is a big day for me. I am happy to join a big team like Kaizer Chiefs,” Castro commented on his new club's official website.
“I appreciate the opportunity to play for Chiefs and I will make sure to repay the confidence and trust the club has shown in me."
The 28-year-old marksman believes it is high time The Glamour Boys return to domestic glory and start competing on the African continent, and hopes to contribute to their future success.
“Big teams like Chiefs need to win trophies and participate in international tournaments like the African Champions League," he added.
"The club is very professionally run and I want to bring my goals to help the team succeed. I want to help Chiefs win championships.”
He will look to do damage upfront for the Soweto giants along with the likes of fellow South American Gustavo Paez and Bernard Parker.
Amakhosi have recruited Castro and midfielders Siphelele Ntshangase and Kabelo Mahlasela this transfer window, while they have promoted left-back Siphosakhe Ntiya-Ntiya from their development ranks.
Mahlasela, however, faces a spell on the sidelines with a seemingly serious knee injury.