Derek Darvell, from Hamilton, took part in the event, which held its first competition for people with disabilities, in Paris.
The 27-year-old faced competitors from 13 countries in the kata section, where the athlete performs a set series of blocks and counter attacks against an imaginary opponent.
He said: "I feel proud and my family are proud of me. To go out in front of 12,000 people and to do kata is challenging. Scotland has never had anyone take first, second or third in the WKC and to come third is a big achievement."
Asperger syndrome is a form of autism, a lifelong disability that affects how a person makes sense of the world and often brings about challenges in communication.
Derek uses karate to help break down the barriers of his condition and has already gained his second level black belt and won karate titles in the Scottish Championship and British National Open.
The second-year business student at the University of the West of Scotland hopes to become a karate instructor for others with disabilities.
He said: "Karate gives me a lot of discipline and allows me to progress into areas of my life which I'm very keen to get better in.
"The better I do in my karate, the higher I move up in areas outwith my karate.
Derek's next big competition, The International Karate Open, is in Dubai next month. However, as he is self-funded, he is asking for help to raise the £1000 he needs.
Dr Robert Moffat, national director of the National Autistic Society Scotland said what Derek has achieved "is nothing short of amazing".
Terry Connell, president of the Scott-ish Karate Governing Body and Derek's train-er for eight years said: "The Scottish karate community is hoping demonstrations of Derek's skills will help persuade the World Karate Federation to formally introduce a disability section to all its competitions."
To donate, visit Derek's JustGiving site at www.justgiving.com/derekdarvell1