In 2015, Mullins took a youthful squad to the program's fifth NCAA Tournament appearance while under his command. The team also advanced to the second round for the fourth time in school history and the third time under Mullins with a first round upset of Ohio State at the Nashville, Tenn. regional.
Mullins also coached freshman Lily Miyazaki to a memorable freshman campaign as she garnered All-Big 12 Singles Team, Co-Big 12 Freshman of the Year, and ITA Rookie of the Year honors.
In 2014, Mullins led the program to the best season in program history in his sixth year with the program, finishing in the Top 20 for the first time and reaching as high as No. 14. The Sooners reached the second round of the NCAA tournament for the second time under Mullins, and just the third time in program history. In addition, Mullins was named the ITA Regional Coach of the Year and was awarded the National Team Sportsmanship Award.
In 2013, Mullins led the program to the first round of the NCAA Championships with doubles pair, Whitney Ritchie and Hermon Brhane advancing to the round of 16.
Mullins coached Ritchie and Brhane to a season high No. 8 ranking. The pair were ranked in the ITA Top 20 for seven weeks straight ending with a No. 9 ranking.
Ritchie and Brhane became Mullins' first All-Americans in 2013 and OU's first since 1988.
OU finished a program-best third place in the Big 12 conference in 2011, with seven individuals and doubles pairs finishing in the top five at their position.
OU also claimed two of the three doubles Big 12 position championships and won two singles position titles under Mullins’ tutelage in 2011.
Mullins led the team to overall records of 18-6 and 19-7 in 2010 and 2011 respectively, which marked just the third time in program history that OU had back-to-back seasons with at least 18 wins.
OU spent 13 straight weeks ranked in the ITA top 25 in 2011 and finished the season ranked No. 24 in the country.
Mullins, the 2008 Intercollegiate Tennis Association Assistant Coach of the Year, was named the head women's tennis coach at the University of Oklahoma in June 2008.
Mullins completed his third season as the assistant coach for the women's team at Northwestern University in Evanston, Ill., in 2008. Mullins helped lead the Wildcats to at least the round of 16 of the NCAA championships in each of his three seasons. In 2007, he was named the ITA Midwest Region Assistant Coach of the Year. During his stint with the Wildcats, NU posted a record of 77-12.
Mullins' three years of success began in 2006 when Northwestern advanced to the quarterfinals of the NCAA Tournament and captured a doubles title. The Wildcats advanced to the round of 16 in 2007 and returned to the quarterfinals in 2008.
Mullins began his collegiate coaching career at DePaul, as the Associate Head Men's Coach in 2005, after working in his native Ireland as an assistant tennis professional at Donnybrook L.T.C. in Dublin for two years. With Donnybrook, Mullins worked with elite junior Irish tennis players and also assisted with the Irish National Team.
Mullins has traveled throughout the world to various ITF and ATP events as both a player and coach to some of Ireland's top junior tennis players. As a collegiate player at Fresno State, he helped the Bulldogs to a WAC title in 1999 and a perennial top 20 national ranking. Individually, he advanced with doubles partner Peter Luczak to the NCAA Tournament where the duo earned All-America honors and a No. 9 national ranking in 2001.
Professionally, Mullins was ranked as both a singles and doubles player and was a member of Ireland's Davis Cup team. He played in Davis Cup competition from 1999-2004, representing Ireland against Ukraine, Hungary, Greece, Egypt and Slovenia.
As a junior tennis player, he competed in both the Junior Wimbledon and the Junior French Open.
Mullins graduated from Fresno State with a degree in business and finance in 2001. Mullins and his wife, Laura, have two sons, Liam and Damien.