Murphy helped make history his senior season at Lassiter, as the Trojans repeated as Region 5-AAAAAA champions for the first time. Rivals.com ranked him the 41st-best prospect in Georgia and 43rd in the country at his position. He was ranked as the 49th-best cornerback in the nation by ESPN. He finished his final campaign with 31 tackles, five pass breakups, three forced fumbles, two fumble recoveries and one blocked field goal. A second-team all-region selection as a junior, Murphy recorded 19 tackles, 15 pass breakups, three interceptions and one fumble recovery as Lassiter went undefeated with a 10-0 record during the 2012 regular season. As a sophomore, Murphy registered two interceptions, 13 pass breakups and 27 tackles. He was a five-time academic honor roll selection, has played the violin since kindergarten and participates in volunteer work with special education children. He was coached at Lassiter by Jep Irwin. Murphy was originally recruited by Arkansas, Missouri, Vanderbilt, Oklahoma State, Louisville, Arizona and Washington State.