Marshall was born in Auckland but moved to Nelson as a child, playing his junior rugby for Stoke and Nelson. He was educated at Nelson College from 2002 to 2006 and played in the school's 1st XV in his final two years there. Marshall also came to the attention of national selectors. However, he failed to make the New Zealand Under 17's and Under 19s. It was the same with the New Zealand Under 20s, losing out to Hawke's Bay five-eighth Daniel Kirkpatrick and Waikato's Trent Renata. He is the older brother of CrusaderTom Marshall.
Domestic career
Marshall started his career with Tasman after he made his debut for the Makos 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 No 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’ back-up 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.
