Punza began studying judo at the age of six,[2] attending classes at Lilayi Police College.[2] As an adult, he became an officer in the police service.[2]
In 2015, Punza and fellow Zambian judoka Boas Munyonga traveled to Uzbekistan to study judo, under a scholarship program from the International Judo Federation.[3] Punza and Munyoga were unable to compete in the 2016 European Open Championship, as a result of visa difficulties with the government of the Czech Republic.[4] In spite of this, Punza was able to qualify to compete in the Olympics by scoring enough points in competition to meet the continental qualification quota.[5]
