Which actor played Data's creator, Noonien Soong?

The actor who played Data’s creator, Noonien Soong, was Brent Spiner.

Spiner is best known for playing the android Lieutenant Commander Data throughout Star Trek: The Next Generation, but he also portrayed Data’s human creator. Noonien Soong is a brilliant cyberneticist who designed Data, Lore, the prototype android B-4 and other Soong-type androids. Spiner’s casting made the creator and creation visually resemble one another, reinforcing the story’s themes of inheritance, identity and the limits of artificial life.

The character appears prominently in the TNG episode “Brothers,” in which Data is summoned to Soong’s remote laboratory. Soong is dying and has called Data there to install an emotion chip, but Lore also arrives and disrupts the plan. Spiner plays Data, Lore and Soong in the same story, a demanding multi-character performance that required careful staging and distinct physical mannerisms.

The answer is sometimes confused because several Soongs appear across Star Trek. Brent Spiner later played Soong ancestors Arik and Adam, as well as Noonien’s son Altan Inigo Soong. Those are separate characters, but the actor remains the same. Fionnula Flanagan, not Spiner, played Noonien’s wife Juliana Soong.