In-Sik is the former Head Volleyball Coach at Christian Brothers University where he coached for 18 seasons and earned the GSC West Coach of the Year Award in 2010,2012, and 2016. In 2010 he led the Lady Bucs to a 9-3 GSC West mark that was the best finish in 14 years of GSC West play for CBU. Hwang has coached 20 All-GSC players and five Academic All-GSC players at CBU. The 2006 Lady Bucs placed their entire roster on the GSC Fall Academic Honor Roll, the only GSC team in ANY sport to achieve that honor. In 2008 Hwang broke the record for most wins in a season and in 2011 he became the winningest volleyball coach in CBU history. The 2011 season highlights included an appearance in the NCAA tournament for the first time in school history. Additionally, three members were placed on the ALL-GSC team, 2 were named All-Region, and one All-American. In the 2012 season his team played for the Gulf South Conference Championship and made their second appearance at the NCAA tournament advancing to the semifinals thus placing in the top 32 teams. 

Before accepting the position as Head Volleyball Coach at CBU in 2002, In-Sik was the Head Volleyball Coach at LaVergne High School where he was honored as the Conference Coach of the Year in 2000 and 2001. He was also honored as the Conference Coach of the Year at Franklin High School in 1999. In-Sik graduated with a B.S. in Physical Education in 1998 from Middle Tennessee State University where he held the position as Assistant Volleyball Coach and helped guide the Blue Raiders to their first NCAA Tournament appearance in 1995.