Getting the right actor to play Spock turned out to be surprisingly easy.
A short video on Zachary Quinto‘s website explained the casting of Quinto as Spock, from Quinto’s viewpoint as well as from the viewpoint of others like J.J. Abrams, Alex Kurtzman, Bryan Burk and Leonard Nimoy.
“When he came in and read, he was just so perfect,” said Kurtzman. “He was undeniably perfect.”
“There were strangely moments when he actually looked like Leonard [Nimoy,] said Burk. “Like when his head was tilted at certain angles.”
“Well, they sent me some footage of him,” said Nimoy. “I immediately saw there was enough resemblance and a load of talent.”
Source: Zachary Quinto Official Website