An equine expression
Any career on the fast track is firmly rooted in etymology.
The word's 16th-century origin came from the French carrière and originally meant a chariot road. For the next three centuries its sense ranged from a highway, to a place for exercising on horseback (usually at full speed), to a gallop. Back then, wild horses might "career" through a field.
But quite naturally the modern sense of "a course in one's life" as in "occupation" wasn't far behind the stampede. It appeared in general usage in the early 1800s.
SOURCES: 'Word Mysteries and Histories,' by the Editors of American Heritage Dictionaries; 'The Barnhart Dictionary of Etymology,' by Robert K. Barnhart.