Born in Salford, Manchester, Robert James-Collier earned an undergraduate degree in business at the University of Huddersfield before obtaining his master’s in marketing at the University of Manchester Institute of Science and Technology. Soon, he was bored of the corporate world and began pursuing a career in acting by taking classes after work through the Yellow Pages.
In 2005 he made his acting debut as Alex in the television movie, Perfect Day. The same year, he landed a recurring role on Down to Earth, playing Nicky, a womanizing landlord. He appeared on Coronation Street from 2006 to 2008 in the role of Liam Connor, winning "Sexiest Male" in both 2007 and 2008 for the role, as well as "Best Exit" in 2008 at the British Soap Awards.
In 2010, he was cast as Thomas Barrow, a footman on the popular ITV series Downton Abbey, which ran for six seasons to 2015. He continued to reprise the role in both sequel films, Downton Abbey (2019) and Downton Abbey: A New Era (2022). Alongside the cast of Downton Abbey, he won Screen Actors Guild Awards for Outstanding Performance by an Ensemble in a Drama Series in 2013, 2015 and 2016.
In 2014 he ran in the London Marathon for Chilterns MS Centre, an independent charity that helps people suffering from multiple sclerosis.
He is married to his long-term partner, Lauren Chandiram. They have one child together.