Fingleton was born in Durham, England, in 1980, to mother Christine and father Michael. He had an older brother, Michael, and an older sister, Keely. Fingleton decided to attend high school in the United States after attending a basketball camp in Connecticut when he was 16. In 1997, Fingleton moved from Durham to Worcester, Massachusetts, and began attending Holy Name Central Catholic High School, graduating in 2000. Fingleton's coach was J. P. Ricciardi, who would later become general manager of the Toronto Blue Jays baseball team. Fingleton helped the Holy Name basketball team to the Central MassachusettsDivision I title and a berth in the Massachusetts final game in 1999, and a 22–4 record in 2000. Fingleton was awarded a basketball scholarship to the United States first playing at the University of North Carolina at Chapel Hill and later at the College of the Holy Cross in Worcester, Massachusetts. In August 2000, Fingleton had back surgery and then earned a medical redshirt from North Carolina. Fingleton played only one game with North Carolina then transferred to Holy Cross in 2002. Fingleton graduated from Holy Cross in 2004 with a degree in history. Fingleton debuted professionally in the 2004–2005 season with the Boston Frenzy of the ABA. The Frenzy waived Fingleton in December 2004. In the 2005 NBA Development League Draft, the Austin Toros selected Fingleton as the eighth pick in the fifth round. On 6 December 2005, Fingleton started playing with the English Basketball League team Tees Valley Mohawks. In November 2006, Fingleton signed with Spanish team CB Illescas and later with Ciudad Real. After an injury forced him to retire in 2007, he returned to his home city of Durham to pursue a career in showbusiness. On the Guinness World Records website, Fingleton says:
I am one of three siblings – my sister who is 6'3" is the eldest at 30, my brother is 6'8" who is 29 and I am 7'7" at 26... my mother is 6 foot and my father was also. My great grandfather was 6'8". I have always been taller than everyone since I can remember. My height really took off when I reached 11 and was touching 7 foot. By the time I was 16 I was 7'5" and stopping growing at 18 when I was 7'7.56. I have never been self conscious about my height. I am more conscious of going bald so that should tell you. I never let my height play a negative part in my life. I always do what I want, some tall people may be restricted as they are constantly stared at or people ask the same questions over and over. This is the only bad thing about being tall – the stupid remarks and questions. Other than that, being tall is great. I have been doing acting work since my basketball career finished. I spent eight years in the USA attending High School and College. I graduated from the College of the Holy Cross in 2004 with a degree in History. I have played professionally in Greece, Italy, Spain. Now I am concentrating on acting and trying to move to LA soon to jump in with both feet so to speak.
Two 2007 British TV documentaries, Britain's Tallest Men and Superhuman: Giants featured Fingleton and covered the difficulties and constant attention, quite often considerable rudeness, that he faces day to day. He appeared in the film 47 Ronin, starring Keanu Reeves. From 2014 to 2017 Fingleton played the giant Mag the Mighty in the TV seriesGame of Thrones. He also appeared in the 2015 film Jupiter Ascending, starring Channing Tatum and Mila Kunis. He played Russian General's Bodyguard 1 in the Fox Studios film ', and he provided the motion capture for the CGI character Ultron in the Marvel Studios film '. Fingleton appeared in a two-part serial written by Toby Whithouse for the 9th series of Doctor Who, filming in January 2015 in Cardiff. He played the villain "The Fisher King", an alien warlord. The series was transmitted in autumn 2015.