Beecham was born in Manchester, Greater Manchester. Her father is English and her mother is American from Arizona. In 2003, at the age of 18 she enrolled at the London Academy of Music and Dramatic Art (LAMDA) for three years, graduating with BA Hons in 2006.
In mid-2007, she was chosen by Director Jan Dunn for the leading role in her independent film The Calling which she won Best Actress Award for at London Independent Film Festival. She was a recipient of the Edinburgh International Film Festival Trailblazer Award. The film received mixed reviews, one of which commented that "newcomer Emily Beecham plays a young woman determined to take the veil and holds her own well against such stalwarts as Brenda Blethyn and Susannah York". In highlighting the impression made by Beecham, film columnist Hannah McGill, who served as the Edinburgh Festival's artistic Director from 2006 to 2010, decided that she should be one of the recipients of the coveted Skillset Trailblazer Award. That same year, Beecham gave her first professional stage performance in Ian McHugh's debut play, How to Curse, at the Bush Theatre in Shepherd's Bush, London, directed by the theatre's artistic Director Josie Rourke.
In 2013, Beecham starred as Caro Allingham in The Village. She currently stars as The Widow in the AMC martial arts action drama series Into the Badlands.