Ser Hugh, also called Ser Hugh of the Vale, is a character in Game of Thrones. He is played by Jefferson Hall and appears in the first season.
Hugh served as Lord Jon Arryn's squire for four years before Jon Arryn's death. After Arryn's death, Hugh was knighted for his loyal service by King Robert Baratheon. When Lady Lysa Arryn returned to the Eyrie with her son, Ser Hugh elected to remain in King's Landing in the King's service.
Season 1
Cripples, Bastards and Broken Things
Lord Eddard Stark sends Jory Cassel to quiz Ser Hugh about Jon Arryn's death. Ser Hugh refuses to talk to Jory since he isn't a knight. Ser Hugh takes part in the tournament to celebrate Eddard's arrival and is killed in a 'tourney mishap' by Ser Gregor Clegane.
The Wolf and the Lion
Lord Commander Barristan Selmy stands the knight's vigil for Ser Hugh. Eddard ponders how Hugh could afford arms and armor so soon after being knighted, leading him to suspect that Hugh was involved in Jon Arryn's death. Varys later agrees that this is the most likely explanation, and that the Lannisters ordered him killed to prevent him talking.
In the books
In the Song of Ice and Fire novels, Ser Hugh is a reasonably effective warrior but is newly-proud and slightly drunk on his achievement of becoming a knight.