Spirit Jr. is a wild buckskin mustang stallion who has shared a close bond with Lucky since Lucky's return to Miradero at the age of twelve. He is the male protagonist of the show. Lucky named Spirit because he was a horse of fiery independence whom no one else had been able to tame, despite attempts by Mr. Granger and his mesteñeros.He disgreed with Mr. Granger to be ridden on, or accompanied, and refused to eat anyting.
Even while accompanying Lucky and the PALs on their adventures, Spirit protected a wild herd of mustangs that range outside Miradero. When Lucky ran away from home to join the circus, Spirit ceded his role with the herd to the rival stallion Smoke, and did not immediately rejoin the herd upon returning to Miradero with Lucky later the same summer.
Spirit Jr. is the son of Spirit from Spirit: Stallion of the Cimarron, his mother is Rain, his younger sister is Tabitha, his niece is a filly named Presley, and his grandmother is Esperanza.
His personality is like his father's; wise, kind, brave, stubborn, protective and loyal. He loves his friends and will go to great lengths for them. In coincidence, he and his father both share the same name. Mr. Granger had said that the horse has a lot of spirit, then Lucky had named him Spirit because of his determined personality.
Spirit Jr. is the most muscular horse in the series and has his father's buckskin coat, black legs, dark brown mane and flashing brown eyes. However, he also has his grandmother's white blaze. As Rain doesn’t have a blaze due to her being a paint.
His father was a Kiger Mustang and he's a Kiger Mustang.