Marshall started his career with after he made his debut for the Mako in the
2008 Air New Zealand Cup competition, coming on as a replacement against
Bay of Plenty. In 2009 he suffered an injury in the first match which kept him out for most of the season, but went on and made his first full game against
Taranaki. During the
2010 ITM Cup he made an immediate impact with his decisive running and ability to spot a gap. His strong performances saw him take over
Fly-half, mainly starting in the number 10 position throughout the season. Marshall left for Italy to begin a six month contract with
Aironi Rugby after his name was missing from
Super 15 squad selections. He spent five months playing for the side, making several
Heineken Cup appearances and also featuring in the
Celtic League. However he continued his career with Tasman during the 2011 season before he headed north on a two-year contract with
Taranaki, having played 36 games and scored 46 points for the side. He made his debut for
Taranaki, playing the season's first two
Ranfurly Shield matches against
King Country and
Wanganui. His performances didn't go unnoticed by the national media or the
Super Rugby coaches as he went on to play all 12 matches and score 5 tries. Marshall's versatility and high standard of performance in several positions, including
wing, first five-eighth, fullback and
second five-eighth helped him win Taranaki back of the year for 2012 ahead of finalists Frazier Climo and
Jamison Gibson-Park. His form for
Taranaki in the number 10 jersey in
Beauden Barrett's absence saw him pick up a
Hurricanes contract in late 2012. He played his first
Super Rugby match in the Hurricanes 29–28 victory over the
Crusaders in Week 4 of the
2013 competition. He had an eye catching debut season, starting the season as the Hurricanes backup
first five-eighth behind Taranaki teammate Beauden Barrett and ending it by making three straight starting appearances at fullback. In all, he started or came off the bench in eight matches out of 16 in 2013. Marshall made two starts for the Hurricanes at fullback in 2014, before captaining Taranaki to win their maiden
ITM Cup premiership title. On 6 January 2016, it was announced that Marshall would join the
Greene King IPA Championship side
London Irish ahead of the 2016-17 season. The Hurricanes went on to win the
2016 Super Rugby season for the first time. He returned to the Hurricanes for the
2019 Super Rugby season. He was not named in the Hurricanes squad for the
2021 Super Rugby season. Marshall returned to for the
2020 Mitre 10 Cup but it was announced he would miss the season with injury. The Mako went on to win their second premiership title in a row. ==International career==