What age did the dog who played Lassie die?

The first dog to play Lassie died in 1958 at the age of 18. The current Lassie, nicknamed Mason, appeared in the 2005 film with Peter O'Toole and is still alive.

There were several dogs to play Lassie, it just was not one dog. The first dog who played Lassie was named "Pal" in 1943. Pal appeared in movies from 1943 to 1951, and in the pilots for the first TV series in 1954. Pal was bred to continue the look of Lassie. Eight generations of Pal and his descendants portrayed the beloved collie in two television series and ten movies, through the late 1990s.