Rob Whistle played two seasons of Junior with the Kitchener Rangers then he mixed hockey with education by enrolling at Sir Wilfred Laurier University. After four seasons of collegiate hockey, Whistle signed a free agent deal with the New York Rangers and began his professional career.
During his rookie season Whistle split his time between the New Haven Nighthawks of the American Hockey League and the NHL. Whistle played 32 games on the Rangers blue line and was able to contribute four goals and six points. That spring he suited up for his first NHL playoff games as well, but was held scoreless in three matches. After spending all of the 1986-87 season with the Nighthawks, Whistle was traded to the St. Louis Blues in exchange for Bruce Bell and future considerations.
With the Blues he played just 19 games, but matched his previous output of six points and appeared in a single playoff game that spring. Whistle spent the majority of that season with the Blues farm club in Peoria and that was where he began the following year as well but just four games into the schedule, he was on the move again. This time his destination was Washington, but he spent all of that campaign with their farm club and retired at season's end.