Born in Dewsbury, England. This former professional extreme sports athlete was named by his uncle after the Oscar winning 1950s American Actor Dean Jagger, and chose the same profession for himself. Jagger began acting in school productions at age 14 after, by chance, he met actor Michael Douglas while sailing with his father off the coast of Spain. He joined the theatre, appearing in numerous stage productions. He was born with skills of a sportsman, trained in boxing from the age of 16. After finishing school, Dean became a professional skater. He travelled the globe, competing and placing in events such as, the X-Games and the Walt Disney Skating Challenge.
After a few years of being on the pro circuit, he returned to England to fulfill his desire to act. He joined British Actor's Equity and studied in London at The Actor's Centre and Penelope Jay's School of Performing Arts. He also studied in the U.S. His younger brothers are also involved in the show business; Ben is a professional stuntman and Lee is a theatre actor; both perform in the UK.