Raised in Canada, Lettieri began his pro career with the Minnesota Kicks in 1977 and played there until 1981. He went on to play the Vancouver Whitecaps in '82 and '83 and the Minnesota Strikers in '84. He was named NASL North American Player of the Year in 1983 and had the league's best Goals Against Average in both '82 and '83.
Lettieri was a regular in the original MISL. He continued to play for the Strikers as the team joined the indoor league, playing the 1984-85 season through to 1987-88. Lettieri was voted Goalkeeper of the Year for the 1986-87 season.
Lettieri is often remembered for his keeping a stuffed parrot in the back of his net during games. The bird was named 'Ozzie'. In 1985 the League banned Ozzie II from the nets. Tino married Michelle Nanne, daughter of famed North Star player and General Manager, Lou Nanne. Lettieri now runs a successful food products business out of Burnsville, Minnesota.