Alexander Douglas Smith is an American former football quarterback who played in the National Football League (NFL) for 16 seasons. Smith played college football for the Utah Utes, earning first-team All-American honors and winning the 2005 Fiesta Bowl as a senior. He was selected first overall by the San Francisco 49ers in the 2005 NFL draft.

The quarterback, colloquially known as the "signal caller", is a position in gridiron football. Quarterbacks are members of the offensive platoon and mostly line up directly behind the offensive line. In modern American football, the quarterback is usually considered the leader of the offense, and is often responsible for calling the play in the huddle. The quarterback also touches the ball on almost every offensive play, and is almost always the offensive player that throws forward passes. When the QB is tackled behind the line of scrimmage, it is called a sack.