• Birthplace: London, England, UK
• Age: 42
• Height: 169
• Weight: 0
• Website: N/A

Born in London, England, Hayley Elizabeth Atwell has dual citizenship of the United Kingdom and the United States. An only child, Hayley was named after actress Hayley Mills. Her parents, Alison (Cain) and Grant Atwell, both motivational speakers, met at a London workshop of Dale Carnegie's self-help bible "How to Win Friends and Influence People". Her mother is English (with Irish ancestry) and her father is American; he was born in Kansas City, Missouri, and is partly of Native-American descent (his Native American name is Star Touches Earth). Her parents divorced when she was age two. Her father returned to America and Hayley remained with her mother in London, but she spent her summers in Missouri with her father. Hayley's mother saw theater as an important communal experience, so she was introduced to theater from a young age. At age 11, she had memorable trip to see Ralph Fiennes playing Hamlet. She would later work with him on The Duchess (2008).

She went to Sion-Manning Roman Catholic Girl's School in West London where she excelled academically. She took her A-levels at the London Oratory School. She took two years out of her education, traveling with her father and working for a casting director. In 2005, she graduated from the Guildhall School of Music and Drama with a degree in Acting. Hayley began her career with parts on a few BBC television productions. Her first big break came in the television miniseries, The Line of Beauty (2006). The following year, she got her first film role in How About You... (2007). She followed this with Woody Allen's Cassandra's Dream (2007). Her breakthrough role came four years later as British agent Peggy Carter in Captain America: The First Avenger (2011).