Smokey is a bear with a mission. His mission is to protect the forests and nature from wildfires, which are mostly started by the carelessness of human beings. Smokey tries to educate people especally young children, by making public apperences and appearing in advertisments to make people more aware about forest fires.
When a bear cub was found after a forest fire and taken to a veterinarian he started calling him Smokey Bear, hearing about this survivor the United States Forestry Service adopted him as their mascot (they had been using Bambi before that) in 1944.
Living to the age of 27, Smokey Bear got so much mail that he was given his own zip code and has been said to be the most recognizable iconic figure to Americans after Santa Clause.
By the way, for the record, his name is Smokey Bear, the Forestry Service does not aknowlage the "The" which was only added in a popular song in the early 50's so it would rhyme better.