Her appearances in television programmes include the role of Anna Thornton-Wilton in the BBC television drama Hotel Babylon, and SunTrap, Days Like These, Beast, I Saw You, Charles II: The Power and The Passion, The Worst Week of My Life, Bloodlines, Coupling, Time Gentlemen Please, Dead Boss and Killing Eve.
Her father, Charles, was stationed at Faslane Naval Base on the Clyde where Emma spent the first four years of her life.
After leaving school in 1997, Pierson performed in amateur productions with the North Bradley players, appearing in a number of plays including Chekhov's Uncle Vanya.
Pierson gained the role of Becky Radcliffe in the BBC children's drama series Grange Hill while studying law at the City of Bath College.
After leaving Grange Hill, Pierson took on the role of Jackie Burgett in Days Like These, an ITV sitcom set in Luton and adapted from the American comedy series That '70s Show.