Born in Tweed Heads, New South Wales, Simpkins played his junior football for the Currumbin Eagles, Tugun Seahawks and came up through the Tweed Heads Seagulls Colts system before being signed by the Gold Coast Titans.

[6] After coming off the bench for the first six games of his career, Simpkins started at second-row against the St. George Illawarra Dragons and scored his first NRL try in Penrith's 13-12 golden point victory.

On 21 September 2014, Simpkins was named at lock in the 2014 NSW Cup Team of the Year.

[7] On 28 September 2014, Simpkins played in Penrith's 2014 New South Wales Cup Grand Final win over the Newcastle Knights,[8] also playing in the Panthers' 2014 NRL State Championship loss to the Northern Pride RLFC on 5 October 2014.

[9] On 9 October 2014, Simpkins signed a 2-year contract with the Gold Coast Titans to return to his original club starting in 2015.