2009-10: Drafted by Sarnia in the fourth round of the 2009 OHL Priority Draft, Jamie Phillips instead played junior A hockey with Welland and Brantford. In six OJHL games with Welland he was 0-2 with a 4.76 goals against and .886 save percentage. He played in three games for Brantford and was 2-0 with a 3.00 goals against and .873 save percentage.
2010-11: Phillips was the winningest goalie in the junior A Central Canada Hockey League as the Pembroke Lumber Kings won the regular season and playoff titles. In 33 regular season games he was 25-7 with six shutouts and had a 2.13 goals against and .913 save percentage. Mid-season acquisition Francis Dupuis, a 20-year-old, handled the bulk of the goaltending duties in the post-season. In two CCHL playoff games, Phillips was 2-0 with one shutout and had a 1.50 goals against and .919 save percentage. Phillips appeared in two games during the Fred Page Cup en route to the RBC Cup and stopped 20 of 26 shots for a 6.00 goals against. Dupuis started all six games at the RBC Cup as the Lumber Kings captured the national championship.
2011-12: Phillips began the season in the BCHL with the Powell River Kings before returning to Ontario in a mid-season trade. He finished the season with the OJHL's Toronto Junior Canadians. In December, prior to the trade, Phillips committed to attending Michigan Tech in 2012-13. In 26 games with the River Kings, he was 16-6-1 with 5 shutouts, a 2.01 goals against average, and .921 save percentage. In 11 games with the Junior Canadians, he was 4-6 with 2 shutouts and had a 3.11 goals against and .917 save percentage. He started all ten playoff games for Toronto and was 5-5 with a 2.99 goals against and .932 save percentage. Ranked 26th amongst North American goaltenders in Central Scouting's final rankings prior to the 2012 NHL Draft, Phillips was selected by Winnipeg in the seventh round (190th overall).
Phillips is in his freshman season at Western Michigan University.