Lim is a 5 ft 11 in, 175 lb right-handed pitcher. Lim is known as the fastest sidearmpitcher in baseball history who can throw a 160 kilometres per hour (99 mph) four-seam fastball, though the pitch usually sits at 93-95 mph (150-153 kph). His signature pitch is his two-seam fastball which, due to its unique tailing movement has earned its nickname "Serpent fastball (Hangul: 뱀직구)". His other pitches include a high 70s slider with a sharp horizontal break, a mid 80s forkball, and a rarely used 60 mph (97 km/h) slow-curveball. He is one of the few pitchers who can pitch in multiple pitching forms. Lim pitches primarily sidearm and underhand, but does pitch from the three-quarters motion at will.
Though predominantly known as a closer, Lim was converted to a starting pitcher in 2001, and spent three years as the Samsung Lions' starter before returning to the bullpen in 2004. There was interest from Major League squads, but Lim decided to stay in South Korea.
In late 2007, Lim was signed by Japan's Tokyo Yakult Swallows in the hopes of bolstering their weak bullpen. In the 2008 NPB season, he recorded 33 saves (5th in the NPB league) with a 3.00 ERA in 51 innings pitched.
In the 2009 NPB season, he recorded a 0.00 ERA for a few months, earning his nickname "Mr.Zero", and also featured in the 2009 NPB All-star Game as a closer for the Central League team. He was sent down to the reserve squad after his ERA rose to a whopping 1.84 in a short stint, but was brought back to strengthen Yakult's weak bullpen, which was responsible for its recent losses.
Lim had his second Tommy John surgery in July 2012. After the 2012 season, Lim agreed to a contract with the Chicago Cubs of Major League Baseball. The Cubs promoted Lim to the major leagues on September 4, 2013. After the season, Lim was non-tendered by Chicago, becoming a free agent. The Cubs re-signed him to a minor league contract. He was released on March 24, 2014.