As a kid, Koo Ja-myung was a very goal-oriented boy. Thanks to his cheerful personality, he was liked by many friends. A sports enthusiast, he played on the school basketball team (Gyeonggi Middle School) and baseball team (Gyeonggi High School). In particular, his experience playing baseball made him realize something. One day, the Gyeonggi High School team, made up of regular student players, faced off against the mighty Gunsan Commercial High School and Seonrin Commercial High School, both made up of professional players. Although they were defeated, the Gyeonggi High School's baseball team played the game well even without outstanding players based only on teamwork and cooperation. Koo learned the power of passion and cooperation through this event

Koo Ja-myung admired his father, Koo Tae-hoe, who had a highly reputed political career. Hoping to follow his footstep, Koo entered Seoul National University as a Political Science student. In an era of political turmoil, Koo, a young man with grand dreams, set his aspirations to become a clean and dignified politician. In order to serve the country and develop leadership, he joined the school corps and fulfilled his military duties as an artillery officer. At the time, this was a very rare case for the son of a social leader, which was why it was praised as an example of noblesse oblige.

After being discharged, he studied abroad in the United States, a politically advanced country, and received a master's degree in political science from the prestigious Fairleigh Dickinson University Graduate School. After deliberating thoroughly on the rapidly changing political situation in Korea, he changed his goal from becoming a politician to becoming an entrepreneur. He then earned his master's degree in Mathematics and Public Administration from The George Washington University Graduate School.

In 1983, he began his career at Chevron in the United States, after which he gained practical experience at LG Oil Refinery (now GS Caltex), LG International, and Kukdong City Gas (now YESCO).

In 2005, Chairman Koo Ja-myung (then Vice Chairman) took office as the CEO of LS MnM. The appointment took place because the senior management agreed that his experience and capabilities would be useful in the copper smelting industry, especially when it comes to securing overseas resources and global trade. The chairman devoted himself to leading managerial innovation based on communication, while strengthening the global network by participating in the International Copper Association (ICA) as an executive. Thanks to these efforts, the company's sales, which were about 2 trillion won before his appointment, grew remarkably to 9.5 trillion won in six years. On top of this, starting in 2008, he expanded the company's area of business to metal recycling and overseas resource development, in addition to strengthening its R&D capabilities. In 2010, the company initiated its goal to become a ‘global leader in the world metal industry’ and launched the ‘2020 20 2 Project.’

Chairman Koo was also passionate when it came to external activities. He served as the chairman of the Korea Non-ferrous Metal Association from 2005 to 2008 and as a director of the International Copper Association from 2006, striving to contribute to the development of the non-ferrous metal industry both home and abroad and to create new demand for copper. In 2010, he led a copper antibacterial clinical trial project, followed by a copper alloy fishing net test project for floating fish cages.

In his keynote speech delivered at the 2009 IWCC (International Wrought Copper Council), he emphasized the importance of coexistence of mining and smelting industries, leaving a strong impression on the global copper industry. This served as an opportunity for LS MnM to receive the spotlight of the global copper industry.

In the same year, he started serving as an honorary consul in Korea for Chile, the world's largest producer of copper ore, and contributed greatly to friendly exchanges between the two countries. His efforts and achievements were recognized with the ‘Copper Man of Year’ award, the highest honor in the global copper industry. Chairman Koo became the first Korean and the third Asian to receive the Copper Man Award, an award given annually to a person who has made the most outstanding achievements and contributions in the world's 200-trillion-won copper industry.

To his employees, he was a leader who was always caring and full of energy. He would visit the plants and sites, listening to the ideas and stories of the employees, and even participated as an interviewer in the recruitment process. He planted dreams in the minds of new employees as he ate lunch together, and participated at company sports competitions and year-end parties. Through these events, the chairman encouraged the employees by showing passion and instilling the importance of cooperation.

We miss his enthusiasm, his energy. We remember how he would sing as he drank with the employees, how he would introduce himself as “My name is Koo Ja-myung, and I’m from Pyeongchang-dong” as he cheered alongside us during the World Cup. We remember how pleasantly shocked we were when he gladly treated a new employee to a dinner when she made the bold request at a company sports event. And we remember how devastated we were when he left us so suddenly. But we know that he will continue to aspire us, encourage us, and lead us.