Rim Chung was born in a coastal village of Kum Nam, North Korea on March 15, 1934. The village's name translates to Golden Orchid. As a child Chung fished for snapper and rock bass from the sea with bamboo roads. During the Korean war, Chung and his family fled to South Korea where he lived for seventeen years. Chung moved to Denver, Colorado in 1968 on a business visa.

In 1970, a friend introduced Chung to fly fishing. He soon decided to design his own fly and developed the RS2 nymph pattern in 1975. The RS2 became a popular pattern in the flyfishing community because of its similarity to a real-life mayfly nymph. Chung fished exclusively with the nymph method of fly fishing and used a rod setup that employed two flies at the same time. He also advocated for the use of light action rods, from zero weight to three weight. Chung has suggested that these rods transmit the best experience while fighting a fish because the fish are more powerful on smaller rod sizes. He also used a level line, which provides a comparably lighter feel than a standard fly line and creates drag. Fishermen also experience less weight and fatigue while using the level line.

Rim Chung and his fly fishing methods have been featured in newspaper articles and books including The Denver Post, The Colorado Springs Gazette, and other news articles and magazines. Chung was also featured in a variety of books including Colorado Trout Flies, Tying and Fishing Tailwater Flies, and Introduction to Saltwater Fly Tying.