Ma Jung-kil (Hangul/Hanja/Romanization: 마정길/馬正吉/Ma Jeong-gil; born March 13, 1979 in Cheongju, Northern Chungcheong Province) is a South Korean sidearm relief pitcher who plays for the Nexen Heroes in the Korea Baseball Organization. He bats and throws right-handed. He is a member of Jangheung Ma Clan (장흥 마씨/長興馬氏), originated from Jangheung County, Southern Jeolla Province where the legendary Lotte Giants baseman, Ma Hae-yeong (마해영/馬海泳) originated the same clan as Jung-kil.
Precisely to say that Jangheung Ma Clan produces skillful and well-honed baseball players in Korea. Apart of Ma Hae-yeong and Ma Jung-kil, there are another three Jangheung Ma Clansmen played for the Korean Baseball League such as Ma Sang-woo (마상우/馬相佑) from Lotte Giants, Ma Nak-gil (마낙길/馬樂吉) from NC Dinos and Ma Yil-young (마일영/馬一英) from Hanwha Eagles.
Ma attended Cheongju Technical High School. In 1997, he was selected for the South Korean junior national team and competed in the World Junior Baseball Championship held in Moncton, New Brunswick, Canada. Ma was drafted by the Hanwha Eagles in 1998 in the 2nd round and as the 111th pick overall.
However, Ma decided to enter the Eagles after graduation from college and continued to play baseball at Dankook University Cheonan Campus in Cheonan Dongnam-gu, Southern Chungcheong Province. During his collegiate years at Dankook University, Ma was considered one of the top sidearm/submarine pitchers along with Chong Tae-hyon of Kyung Hee University. As a sophomore, he was first called up to the South Korea national baseball team for the 3-Nations Invitational Baseball Tournament held in Taiwan.
In 2000, Ma helped his team to win the President's Flag Collegiate Baseball Championship. After the championship, he was selected for the South Korean collegiate national team and competed in the friendly baseball series again the United States national baseball team. As a senior in 2001, Ma led his team to win the National Amateur Baseball Championship where he was named best pitcher.
Upon graduation from Dankook University in 2002, Ma entered the Hanwha Eagles. He had a mediocre rookie season, going 2-5 with 6 saves and 6 holds in 59 games and posted a 5.40 ERA in 60.0 innings pitched as a relief pitcher. In 2003, Ma lowered his ERA to 4.06 and amassed 2 saves and 9 holds appearing in 63 games as a setup man. In 2004, however, he appeared in just 33 games due to injuries. After the 2004 season, Ma left the Unicorns to serve the two-year military service. He joined the Hanwha Eagles again in 2007 when he was discharged from the military duty.
Ma was transferred from Hanwha Eagles to Nexen Heroes in 2010. However, he was sidelined with a left knee ligament rupture in the second half of the 2011 season and missed the entire 2012 season.