Lemmens was born into a family of Indigenous Australian descent (Tiwi).

[2] He progressed his way through the junior ranks at Port Adelaide before solidifying a reserves spot in the 2013.

He debuted for the Magpies senior team in the final round of the 2013 SANFL season.

He was also selected to represent South Australia in the 2013 AFL Under 18 Championships, where he was noticed by Gold Coast defensive coach, Dean Solomon.

[4] Lemmens made his senior debut for the Suns against Richmond in Round 1 of the 2014 season.