Falahee was born and raised in Ann Arbor, Michigan, the son of a speech pathologist mother and a doctor father. He is of Irish-Italian ancestry. Growing up, Falahee attended a Catholic school described as rigorous. He began acting while attending Huron High School. In 2011, Falahee graduated from New York University’s Tisch School of the Arts with a BFA in Drama, where he studied acting and performed in a number of productions, including Love’s Labour’s Lost, A Midsummer Night’s Dream andSondheim’s Company. His first screen acting job was in 2012, with a guest starring role in the comedy web series, Submissions Only. Also in that year he had the leading role in the short film Sunburn. He also studied acting at the International Theater Workshop in Amsterdam.
Falahee made his television debut in 2013, with guest-starring role in The CW teen comedy-drama series, The Carrie Diaries, and later appeared on the short-lived NBC series,Ironside. He starred opposite Haley Lu Richardson and Mary McCormack in the Lifetime movie Escape from Polygamy, which premiered on August 24, 2013. Falahee later had roles in a number of independent films, including Hunter, Blood and Circumstance and Slider. In 2014, he appeared in action-thriller Rage opposite Nicolas Cage and Aubrey Peeples Also in that year he had a recurring role of Charlie McBride on the ABC Family teen drama series, Twisted. He also co-starred as Henri in the 2015 film Lily & Katwith Jessica Rothe and Hannah Murray.
On February 12, 2014, Falahee was cast in the series regular role of ABC legal drama series How to Get Away with Murder produced by Shonda Rhimes. The series starsViola Davis as a law professor. Falahee plays the role of one of the five lead students, Connor Walsh, alongside Aja Naomi King, Alfred Enoch, Matt McGorry and Karla Souza. The series premiered on September 25, 2014 with generally positive reviews from critics and a massive 14 million viewers.
Falahee is also in the upcoming PBS period drama Mercy Street, it airs in January 2016 following the final season of Downton Abbey. He will play Frank Stringfellow, a Confederate soldier scout during the Civil War.
On September 20, 2015 Falahee participated in the Nautica Malibu Triathlon and partnered with Disney to raise money for Los Angeles Children’s Hospital’s pediatric cancerresearch program. Falahee raised over $11,000 in donations for this cause.