The vastly skilled Kirchner will join up with the Men of Gwent in the summer following four seasons at Leinster.
Kirchner has over 30 Springbok Test caps having played fullback, wing and centre at the highest level. He previously played for the Bulls in Super Rugby and the Blue Bulls in the Currie Cup.
Kirchner said: “When looking at the current Dragons squad, the average age and talent within the Region; that is what got me interested. I am keen to find my feet, settle in with boys as quickly as possible, and add value to the squad where I can.
“I believe the Dragons will definitely move in the right direction!”
On the change of scenery from Leinster to Gwent, he added: “New decisions and ventures aren’t always easy to make, however the experience of moving to Leinster, my first move abroad, has helped and knowing a few of the other South Africans in the squad makes my decision easier.”
Dragons Head Coach Kingsley Jones commented: “I am delighted to welcome Zane to the Dragons. His experience both on and off the field will be invaluable for this young squad.
“In addition to his experience, he understands how to win having played a major part in Super Rugby, international rugby and through helping Leinster secure the Guinness PRO12 title in 2014.
“He is a great addition to our young back line and I believe he will bring a much-needed voice in the backs to help these youngsters with their development.”