Jaco Greeff is the founder of Radiyoactive (The first yo-yo manufacturer out of Africa) and the designer of their first yo-yo, the Radiyoactive Fission. In addition he is the owner of Boing Skilltoys a skilltoys store based in Johannesburg, South Africa that acts as a distributor for a wide range of yo-yos. Greeff is also working with modders Eric Wolff and Rob Tsou on Alchemy Yo-Yos
In 2005 Jaco collaborated with Duncan by acting as a producer on the trick CD for the new Duncan line of footbags. Shot in location in South Africa by Mark McBride, this CD features freestyles and tutorial videos by the best footbag players in the country.
Jaco is one of the founding members of the South African Yo-Yo Association, a group of players dedicated to spreading the art of yo-yo play in this region of the world.