Phillips attended Pearland High School. As a senior, he posted 86 tackles, 2 sacks, 2 interceptions, one forced fumble and 2 fumble recoveries. In the Texas 5A state championship game Tre LeDay forced a fumble that he returned 88-yards. He received Houston Chronicle defensive player of the year, Associated Press Sports Editors honorable-mention Class 5A All-state team, All-Greater Houston, district 22-5A defensive player of the year, All-district and Texas High School Football All-elite Class 5A Region III honors.
College career
Phillips accepted a football scholarship from Oklahoma State University. As a true freshman, he appeared in 8 games and missed 5 with an injury. He played mostly on special teams, covering kickoffs and making 6 tackles. He had 10 defensive tackles against the University of Oklahoma. In 2015, he was redshirted. As a sophomore, he appeared in all 13 games at middle linebacker, tallying 42 tackles, 2 sacks and one interception. He started against Texas Tech University and the University of Oklahoma. He had 14 tackles, one sack and one forced fumble against Texas Tech University. As a junior, he appeared in all 13 games at outside linebacker, registering 64 tackles, 9.5 tackles for loss, 42 solo tackles, 2.5 sacks, 2 quarterback hurries, 2 interceptions, 2 pass breakups and 3 forced fumbles. He returned interceptions for touchdowns in back-to-back games against the University of South Alabama and the University of Pittsburgh. As a senior, he was moved back to middle linebacker and was named team captain. He recorded 98 tackles, 11 tackles for loss, 2 sacks, 5 quarterback hurries, 3 pass breakups, one forced fumble and one fumble recovery. He had 12 tackles against Kansas State University and Texas Christian University. He finished his college career with 221 tackles, 6.5 sacks, 3 interceptions, 6 passes defensed, 6 forced fumbles and 2 fumble recoveries in 42 games.
Phillips was signed by the Dallas Cowboys as an undrafted free agent after the 2019 NFL Draft on April 30. On June 18, he was released. On July 31, he was re-signed because of injuries on the linebacking corps. He was waived on August 31, 2019.
Oakland / Las Vegas Raiders
On September 2, 2019, Phillips was signed to the Oakland Raiders' practice squad. On September 25, he was promoted to the active roster to provide depth because of injuries at linebacker and the 12-game suspension of Vontaze Burfict. He appeared in 4 games as a backup, posting 4 tackles on defense and 3 tackles on special teams. On October 29, he was waived with an injury settlement after suffering a season ending knee injury in the seventh game against the Houston Texans. Phillips was re-signed by the Las Vegas Raiders on May 6, 2020.
