[8][9][7] Mitchell began his acting career in 2015, upon graduating high school,[10] appearing in the short films Stereotype (2015) and Fire (2015).

In 2023, Mitchell portrayed the character Michael Gavey in the Amazon Prime original hit-film Saltburn alongside Barry Keoghan as well as Jacob Elordi.

On television, Mitchell made his debut in the 2017 ITV period drama The Halcyon as Billy Taylor.

Later that year, Mitchell starred in HBO's highly anticipated prequel to Game of Thrones, House of the Dragon, adapted from George R. R. Martin's book Fire and Blood.

He took on the role of Prince Aemond Targaryen, a fierce, hot-tempered and dangerous swordsman, the second son and third child of King Viserys I and Queen Alicent Hightower.