Dean Thomas was a “half-blood” boy from London in Harry’s year at Hogwarts.
He was a classmate of Harry’s and best friends with Seamus Finnigan (GF7). He was a black Londoner who grew up as a Muggle, and thus had always been a fan of football (U.S.: soccer) (PS9). At Hogwarts, Dean and Seamus tended to goof around in class a bit (CS6), and both were quite friendly to Harry (PA8). Dean’s home life was kept fairly separate from Hogwarts, and he didn’t tell his parents much about what goes on at school (OP11). He dated Ginny Weasley for a good portion of his sixth year (OP38), but they broke up over petty disagreements (HBP24).
When Harry began being attacked by the Ministry, Dean quietly sided with Harry, despite Seamus being an outspoken critic, and joined Dumbledore’s Army (OP16). He clearly admired Harry for publishing his story in the Quibbler (OP26), and later told other wizards that he firmly believed Harry to be the Chosen One (DH15).
Dean’s father was actually a wizard, though he never told his family this as he feared for their safety; when Dean was a young boy, his father was recruited by Death Eaters and killed when he refused to join, though Dean always thought he had simply walked out (JKR). As a result, when the Ministry began rounding up Muggle-borns, Dean went on the run (DH15). He was captured by Snatchers, until Dobby, Harry, Ron, and Hermione helped him escape to Shell Cottage (DH23). He stayed there, becoming friends with Luna Lovegood (DH25), until returning to Hogwarts to join in the battle against Voldemort (DH29); in that battle, Dean dueled Antonin Dolohov and knocked out at least one Death Eater (DH32).
Hogwarts: Gryffindor, 1991 – 1998; substitute Quidditch team Chaser, 1996-1997 (HBP14, HBP24).
Joined Dumbledore’s Army.
During his 6th year he dated Ginny Weasley until she broke up with him in May of 1997 (HBP24).
Dean is good at drawing (PS), and also “good with the quill” (i.e. can forge signatures) (PA).
His greatest fear has something to do with a severed hand (PA7).
Dean's parents are both Muggles and he has a number of brothers and sisters. The family is a happy and supportive one (offsite web linkJKR).
However, Dean's blood status is not quite what he believes it to be. His biological father was actually a wizard who walked out on the family when Dean was very young, then was killed by Death Eaters when he wouldn't join them. His "father" is really his stepfather and his siblings are stepbrothers and sisters. Dean's mother never knew the truth about Dean's father (offsite web linkJKR).
Dean is good at drawing (PS), and also "good with the quill" (i.e. can forge signatures) (PA).
The role of Dean Thomas is played by Alfred Enoch.