A second-row, he played in the National Rugby League for Sydney clubs the Penrith Panthers, Canterbury-Bankstown Bulldogs and the Parramatta Eels during the 2000s and 2010s.

He played his junior rugby league for the St Clair Comets and Campbelltown City Kangaroos, and attended Eagle Vale High School before being signed by the Penrith Panthers.

Pritchard played the first 5 games of the 2005 season off the interchange bench before regular starting second rower Tony Puletua was side-lined with a season-ending pectoral muscle injury.

Pritchard was selected for New Zealand in the 2006 ANZAC Test, coming off the interchange bench in the Kiwis' 12–50 loss at Suncorp Stadium.

Pritchard was selected to represent New Zealand in the 2006 Tri-Nations series, playing in 4 matches, including scoring a try in the Kiwis 12-16 golden point final loss against Australia at the SFS.

[16] Pritchard was selected to for New Zealand in the 2007 ANZAC Test, coming off the interchange bench in the Kiwis 6–30 loss at Suncorp Stadium.

[19] Pritchard was selected to for New Zealand in the century Trans-Tasman test match at the SCG, playing off the interchange bench in the Kiwis 12–28 loss.

Pritchard was named in the New Zealand squad for the 2008 Rugby League World Cup but didn't play a match in the tournament due to shoulder problems.

[25] In Round 1 of the 2011 NRL season, Pritchard made his club début for the Canterbury-Bankstown Bulldogs against the Wests Tigers off the interchange bench, scoring a try in Canterbury's 24–14 win at ANZ Stadium.

[36] This sidelined Pritchard until Round 26 where he played off the interchange bench in Canterbury's golden point extra time 18–19 loss to the Gold Coast Titans at Robina Stadium.

[37] On 5 October 2014, in Canterbury's 2014 NRL Grand Final against the South Sydney Rabbitohs, Pritchard played off the interchange bench in the club's 6–30 loss.

[3] On 7 May 2016, Pritchard travelled down from Hull to Sydney to captain Samoa in the 2016 Polynesian Cup[48] against Tonga, where he started in the second row in the 18–6 win at Parramatta Stadium.

At the end of the season was selected to captain the Samoa national rugby league team for their 2017 World Cup campaign.

Under Frank's leadership, the Fairfield Pats team clinched the 2022 NRL Schoolboy Cup defeating Hills Sport 20–16 and ending a 30-year championship drought.