He played for the Crusaders in Super Rugby and for Canterbury in the Air New Zealand Cup. He made his debut for the All Blacks at the age of 30 in November 2001 against Ireland and won 22 full caps for the national team scoring two tries.[1] Hewett signed a short-term deal with the Welsh regional team the Llanelli Scarlets in November 2004,[2] playing three times before returning to New Zealand at the end of January. He was expected to return to the Scarlets for the 2005–06 season, having agreed a two-year contract,[2] but he ended up signing a similar deal with Edinburgh in March 2005.[3] He played for the Scottish team until 2007, his last year as professional.
Hewett bought building company Bainbridge Homes in 2014. The firm became insolvent in 2020. In March 2024, shareholders resolved to put the business into liquidation, along with other businesses owned by Hewett: Steadfast Properties, BBH 2020, Module Canterbury, and Absolute Group.[6] A contractor who had worked for the firm said of Hewett, "We were always chasing him for money. He seemed to be teetering on the edge."[6]