Fox's Japanese voice actor is Kenji Nojima, who voiced Shiki Tohno.
For the English voice actors, Wolf's Assault voice actor, Grant Goodeve, also did the Engineer in Team Fortress 2. David Scully, who voiced Leon and Panther in Assault, is known for the roles of Halo's Sgt. Johnson, and Dimitri of the Sly Cooper series.
Speaking of Sly Cooper, Krystal in Assault was voiced by Alésia Glidewell, who played Carmelita in the second game of that series, and Zero Suit Samus*
.]] in Super Smash Bros.. Brawl (also reprising the role of Krystal for her cameos in the Lylat Cruise stage), as well as being the model for Chell, Portal's protagonist (So two Assault actors got parts in two of Valve's major releases. Interesting).
And another Sly Cooper-Valve-Star Fox voice-acting coincidence, Ricky May (who voiced ''Soldier'' and ''Dr. M'') did General Pepper, Wolf O'Donnell and Leon Powalski of Star Fox 64.
Fox's voice in 64 is done by Mike West. You might know his brother Billy as the voice of Fry.