The word ambition traces its roots to ancient Rome and comes from the Latin word ambitiō, which translates to "a going around".  It stems from the verb ambīre (literally, "to go around"), which is a combination of ambi- (around) and īre (to go).  In Rome, ambitiō specifically referred to the practice of politicians canvassing.  Candidates for public office would physically "go around" the city, working the forum, shaking hands, and soliciting votes.  Because this door-to-door canvassing was driven by a strong desire to gain honor, power, and votes, the noun shifted from describing the physical act to describing the strong, inner drive that caused it.  The word entered the English language in the 14th century via Old French.  Interestingly, for several generations in early English, the term had negative connotations.  It was considered a vice associated with arrogance, opportunism, and self-aggrandizement before softening into its modern definition of eager drive and aspiration.  

According to the Oxford English Dictionary (OED), the noun "ambition" was first used in English in the year 1340.  It appeared in the religious and grammatical text Ayenbite of Inwyt (meaning "Prick of Conscience") by Dan Michel of Northgate.  14th Century Origin: The word traces back to Latin ambitio, originally meaning "a going around" to solicit votes or canvass for political office in Rome.  Negative Connotation: For centuries after its introduction to English, it was used as a pejorative term. It referred to inordinate, overreaching desire and was heavily grouped alongside sins like "pride" and "vainglory".  Modern Meaning: The neutral and positive senses we associate with personal career goals and drive are relatively modern.