How did scar get his scar?

According to Disney Villains, in the novel series The Lion King: Six New Adventures, Scar's original name is Taka. In A Tale of Two Brothers, Taka was attacked by Boma's (a Cape buffalo) herd. The biggest of the buffaloes slashes Taka with his horns, knocking him unconscious.

The backstory tells us that Taka is angry that Mufasa is chosen to inherit the throne. Teenage Taka gets angrier when his father chose to solve the drought problems in the Pride Lands instead of going hunting with him.

Taka wanders off to talk to Shenzi, Banzai and Ed, who tell him that if his brother is made to look like a failure, then he will probably be considered to take the throne. Taka then tricks Mufasa into going down to the waterhole, where a Cape buffalo named Boma is rejecting to share the water.

Angelina Jolie and her family took in a recent performance of The Lion King in Sydney, Australia. All six of her children attended the matinee and Angelina "loved" the show and signed the autograph wall. Read more at Broadway World.