He played his junior football for the Western City Tigers and Minchinbury Jets, before being signed by the Penrith Panthers.

[10] After not receiving any game time in the 2016 NRL season, Jennings signed a one-year contract with the South Sydney Rabbitohs starting in 2017.

He made his South Sydney debut against the Manly Warringah Sea Eagles in round 2, scoring a try and setting one up for teammate Robbie Farah.

[13] In round 3 of the 2018 NRL season, Jennings scored his first hat-trick of tries while playing for South Sydney in their 34–6 win over the Manly Warringah Sea Eagles at ANZ Stadium.

[15] Jennings made a total of 18 appearances for the Wests Tigers in the 2019 NRL season as the club finished ninth on the table and missed out on the finals.

[21] In round 7 of the 2023 NRL season, he made his club debut for the Dolphins against the South Sydney Rabbitohs at Suncorp Stadium.