After the highly publicised departure of Chris Sandow, Reynolds joined the Rabbitohs NRL squad in 2012. In Round 1 of the 2012 NRL season, Reynolds made his NRL debut for the South Sydney Rabbitohs against the Sydney Roosters at halfback, kicking 4 goals in the Rabbitohs 24–20 last minute loss at ANZ Stadium. In Round 11, against the St George Illawarra Dragons, Reynolds scored his first NRL career try and also kicked a field goal to win the match for the Rabbitohs 19–18 in golden-point extra time at WIN Stadium. On 16 August 2012, Reynolds re-signed with the Rabbitohs on a 3-year contract to the end of the 2015 season. At the end of season 2012 Dally M Awards he was named the NRL's rookie of the year. Reynolds also finished the season as the NRL's highest goal scorer with 97. Reynolds was also crowned the John Sattler Rookie of the Year and Members Choice Player of the Year at the South Sydney Red and Green Ball in 2012, amongst other awards.  Reynolds played in all of the Rabbitohs 27 matches, scored 3 tries, kicked over 97 goals and kicked 2 field goals in an impressive debut year in the National Rugby League in the 2012 season.