Grice-Mullen has also been a member of the Chicago Bears, BC Lions, Miami Dolphins, Saskatchewan Roughriders, Hartford Colonials and Edmonton Eskimos.
Grice-Mullen attended Rialto High School in Rialto, California and was a student and lettered three times in football and once in track. In football, he played quarterback, running back, and defensive back, and as a senior, he was an All-League selection and an All-County selection. Grice-Mullen graduated from Rialto High School in 2004.
As a freshman for Hawaii, Grice-Mullen appeared in 12 games, starting 11 of them. He led UH's receiving corps with 1,228 yards and 12 TDs. He also recorded five 100+ yard receiving games. During his sophomore year, Grice-Mullen was injured for several games and started a total of nine games. During his junior year, Grice-Mullen caught 106 passes for 1372 yards and 13 TDs. He earned first team All-WAC honors and was part of the WAC's Special Award for Offensive Unit of the Year.
Grice-Mullen places prominently on Hawaii's career receiving lists:5th in career receptions (237)
4th career receiving yards (3,370)
2nd in career receiving touchdowns (36)
On January 8, 2008, he announced that he would skip his senior year of college to enter the 2008 NFL Draft, although unfortunately for him he was not actually drafted.
Grice-Mullen was signed as an undrafted free agent by the Houston Texans shortly after the 2008 NFL Draft. However, he was released on June 13.
On July 24, 2008, Grice-Mullen was signed by the Chicago Bears. He was waived a month later on August 24.
Grice-Mullen was signed to the practice squad of the BC Lions on September 9, 2008, and was later placed on the active roster. During the 2008 season, Grice-Mullen caught 9 passes for 175 yards and 1 TD. Grice-Mullen caught a 67-yard TD pass in the Lions' season finale.
Grice-Mullen finished the 2009 season with 20 catches for 210 yards and one touchdown. In late November, Grice-Mullen set the CFL record for longest playoff punt return when he returned a punt for 106 yards in the second half for a touchdown. He was later named special teams player of the week.
Grice-Mullen signed a contract with the Miami Dolphins on January 6, 2010. The move united with fellow former Hawaii receiver and teammate Davone Bess. He was waived on August 18.
On September 15, 2010, Grice-Mullen returned to the CFL and signed with the Saskatchewan Roughriders.
On August 16, 2011, Grice-Mullen signed with the Edmonton Eskimos after slotback Fred Stamps went down with an abdominal injury