Hollowell had coached Biddy Basketball teams while in high school and decided to continue coaching afterwards.[4] While at St. Edward's, he served as a student assistant coach.[4] He later served one season as a volunteer assistant for the Western Kentucky Hilltoppers, in 2000–01, before returning to St. Edward's as an assistant coach for the 2001–02 season.[5]
Hollowell also coached the Bahrain team Manama Sports Club in 2007, helping them reach the national championship while missing their top player.[6][9] He then worked as the coach of the basketball team at LCC International University in Lithuania for two years (2007–2008), leading them to the playoffs both seasons.[6] He returned to Qatar as head coach of the national youth team in 2009 and remained there through 2010, before moving back to the United States.[4]
Hollowell joined the Loyola Wolf Pack as an assistant coach in 2011.[10] In his first year, he helped them win the conference title and have their first 20-win season since 1948.[5] He was promoted to head coach in 2014.[5] He ultimately served eight years as head coach and compiled an overall record of 166–78, helping them make their first postseason appearance in 71 years and reaching the National Association of Intercollegiate Athletics (NAIA) Tournament in five of his last six years.[11] In 2021–22, he directed them to a record of 37–1 and led them to their first national championship since 1945, as they led the country in scoring and steals.[3] He received a number of honors for the season, including being named national Coach of the Year by the NAIA, the National Association of Basketball Coaches (NABC) and HoopDirt.com, as well as the Don Meyer NAIA Coach of the Year, LABC Louisiana Small College Coach of the Year and Southern States Athletic Conference Coach of the Year.[3]
After the 2021–22 season, Hollowell left to be named the associate athletic director for men's basketball for the Ole Miss Rebels.[12] After one year there, he joined the Texas Southern Tigers as assistant coach.[8] He was hired as the head coach of the New Orleans Privateers in April 2024.[13]