Born in Passaic, New Jersey, Zak threw and batted right-handed, stood 5 feet 10 inches (1.78 m) tall and weighed 150 pounds (68 kg).

In the spring of 1941, he visited a high-school friend, Ed Sudol, who had been signed by the Tarboro Orioles of the Class D Coastal Plain League.

In an interesting coincidence, his manager was named Frankie (Frisch) as was the player with whom he competed for the starting shortstop job (Gustine).

When shortstop Eddie Miller of the Cincinnati Reds was injured, Zak was named as his roster replacement,[3] possibly because the game was being held at Forbes Field, home of the Pirates, and selecting Zak allowed MLB not to have to purchase an extra train ticket.

[4] Zak never appeared in the contest (St. Louis Cardinals' standout Marty Marion played the full game), won by the National League, 7–1.