Marsh started playing cricket at school aged 11 and then progressed to Brighton and Hove CC at 13.
Initially a seam bowler, she made her international debut for England during India's summer tour in 2006. She took 3-44 in her first Test, opening the bowling alongside Jenny Gunn in the second innings.
Having reinvented herself as an off-spinner, she helped England retain the Ashes in the one-off Test at Bowral in early 2008 and go unbeaten that summer, including figures of 4-19 in a one-day international versus South Africa at Shenley.
Marsh aided World Cup and World Twenty20 glory in 2009, taking 5-15 against Pakistan in the former’s group stage.
Although bowling is her stronger suit, Marsh hit a maiden international half-century in an ODI versus Ireland in July 2010. That came between setbacks as she could not prevent England relinquishing the World T20 and Ashes, the following winter.
Marsh helped England rediscover their world-beating form the next summer and winter, and in 2012 made her first format fifty as they were runners-up at the World T20 in Sri Lanka.