Grandmaster Yun began his career in martial arts at the age of twelve.

In Korea, Grandmaster Yun established his first Tae Kwon Do (TKD) club while in the Korean Army.

Grandmaster Yun became an International Tae Kwon Do Federation (ITF) Instructor soon after the formation of ITF

In Hong Kong, Grandmaster Yun established the Kwoon Tong Tae Kwon Do Association and instructed there for three years.

In Malaysia, Grandmaster Yun established three associations: Kelantan, Trengganu, and Pahang States and taught there for three years.

Grandmaster Yun arrived in Australia as the first ITF Tae Kwon Do Instructor to introduce the art to the country.

In New Zealand, Grandmaster Yun established The Master Yun International Tae Kwon Do Federation (MYITF) with over 40 clubs throughout the country.

In Fiji, Grandmaster Yun established the Fiji Tae Kwon Do Association and became one of the leading martial arts organisations in the country.

In Papua New Guinea, Grandmaster Yun established the Papua New Guinea Tae Kwon Do Association in every province and became the leading martial arts organisation in the country.

Grandmaster Yun appointed as Chief Representative and Chief Instructor for the Oceania by the ITF.

In Western Samoa, Grandmaster Yun introduced Tae Kwon Do to the country.

Grandmaster Yun promoted to 8th Dan by the ITF.

In Solomon Islands, Grandmaster Yun introduced Tae Kwon Do and became the leading martial arts organisation in the country.

Elected as the Chairman of the Techniques Committee at the General Meeting of ITF, Grandmaster Yun traveled throughout the world for approximately 9 months of the year for 3 years, promoting the art of Tae Kwon Do. Seminars for the Federation Instructors and Senior Member were conducted regularly until his official resignation in 1987.

In Cook Islands, Grandmaster Yun introduced Tae Kwon Do and became the leading martial arts organisation in the country.

October - Grandmaster Yun officially resigned from ITF after 21 years membership. During his service, he was the:-
Executive Director of the ITF
Chairman of the Techniques Committee of ITF
Chairman of the Merging Committee of the ITF
Chairman of the Expansion Committee of the ITF.

Grandmaster Yun launched Yun Jung Do and established Yun Jung Do International (YJD).

Grandmaster Yun conducted Yun Jung Do introductory seminars throughout the world in most major cities of each countries including Australia, New Zealand, Fiji, Papua New Guinea, Solomon Islands, Cook Islands, West Samoa, Philippines, Taiwan, Hong Kong, Korea, Malaysia, Singapore, Indonesia, India, Sri Lanka, Pakistan, England, Ireland, Scotland, Germany, Poland, United Arab Emirates and United States of America.

Grandmaster Yun developed the diploma of Yun Jung Do and the advanced diploma of Jun Jung Do courses which are accredited by the Vocational, Education, Training and Employment Commission (VETAC) and recognised nationally in Australia.

Grandmaster Yun established the Institute of Yun Jung Do - Australia