"I still am [in shock]," stammered Waltz. "Literally. That's why my answers are somewhat incoherent but I don't care."
Beating out Tommy Lee Jones (Lincoln), Philip Seymour Hoffman (The Master), Robert De Niro (Silver Linings Playbook), and Alan Arkin (Argo), the star said he could barely comprehend the honor.
"I was on a list with the greatest actors around," said an awestruck Waltz when asked about hearing his name called just moments earlier. "How do you think someone feels when all of a sudden, his name is called in that context? I can't tell you."
In Quentin Tarantino's bloody revenge western Django Unchained, Waltz plays a dentist-turned-bounty-hunter who helps a freed slave (Jamie Foxx) rescue his wife (Kerry Washington) from a ruthless plantation owner (Leonardo DiCaprio).
Waltz's Sunday win gives the star two victories for two nominations in just three years.