Who provided Mickey high-pitched voice in the early Walt Disney films starring animated mouse?

Mickey Mouse's high-pitched voice in the early Walt Disney films was provided by Walt Disney himself.

While Walt Disney didn't voice Mickey in every film, he did so in many of the early ones, including Steamboat Willie (1928), Plane Crazy (1928), and The Gallopin' Gaucho (1928).

Later, other voice actors took over the role, but Walt Disney's iconic voice remains the one most associated with Mickey Mouse.