Milligan attended Lake Wales High School, where he played as a quarterback. He received honorable-mention 5A all-state honors as a senior.
College career
Milligan enrolled at Reedley College. As a sophomore, he registered 44 tackles, 3 interceptions and 2 fumble recoveries. He transferred to the University of Alabama at Birmingham after the season. As a junior, he started in 8 out of 12 games, collecting 54 tackles (second on the team), 2 sacks, 4 tackles for loss, and 6 passes defensed. He transferred to the University of Toledo after UAB announced the cancelling of its football program. As a senior, he started in 8 out of 11 games, while playing as a nickelback. He tallied 48 tackles, 2 interceptions, 3 passes defensed and 3 forced fumbles. He had 9 tackles and 2 passes defensed against No. 24 ranked Temple University.
Milligan was signed as an undrafted free agent by the Dallas Cowboys after the 2016 NFL draft on May 9.[1] He was waived/injured on August 4, 2016, and placed on injured reserve.[2] He was released by the team on August 16.
Detroit Lions
On February 9, 2017, Milligan signed as a free agent with the Detroit Lions.[3] He was waived on September 2, 2017, and was signed to the Lions' practice squad the next day.[4][5] He was promoted to the active roster on November 27, 2017.[6] He was waived on December 9, 2017, and later re-signed to the practice squad.[7] He signed a reserve/future contract with the Lions on January 1, 2018.[8] On September 1, 2018, Milligan was waived by the Lions and was signed to the practice squad the next day.[9][10] He was released on September 5, 2018.[11] He was re-signed to the practice squad on October 3, 2018, but was released three days later.[12][13]
Indianapolis Colts
On October 23, 2018, Milligan was signed to the Indianapolis Colts practice squad.[14] He was promoted to the active roster on December 22, 2018, but was waived six days later and re-signed to the practice squad.[15][16] He was promoted back to the active roster on January 9, 2019.[17] On September 2, 2019, Milligan was waived by the Colts and re-signed to the practice squad.[18] He was promoted to the active roster on September 11, 2019.[19] He was placed on injured reserve on December 18, 2019.[20] Milligan signed the exclusive rights tender with the Colts on March 28, 2020.[21] On August 5, 2020, he announced he would opt out of the 2020 season due to the COVID-19 pandemic.[22] On August 6, 2021, Milligan was waived by the Colts.[23]
Saskatchewan Roughriders
On October 24, 2021, Milligan signed with the Saskatchewan Roughriders of the Canadian Football League (CFL).[24] He made his CFL debut in the last week of the 2021 regular season on November 20, 2021, against the Hamilton Tiger-Cats, where he had five defensive tackles, one special teams tackle, and one sack.[25] In 2022, Milligan played in 17 regular season games where he had 71 defensive tackles, 11 special teams tackles, one sack, one interception, and one forced fumble.[25]
Milligan played in the first four games of the 2023 season before suffering a season-ending toe injury.[25][26] In those four games, he had 17 defensive tackles, three special teams tackles, and two interceptions.[25]
