Don Juan DeMarco je mladenič, ki namerava narediti samomor, ko ga zavrne ljubezen njegovega življenja. Trdi, da je najboljši ljubimec na svetu, ki je v svojem kratkem življenju zapeljal več kot tisoč žensk. Na kraj njegovega skorajšnjega samomora prispe psihiater Jack Mickler in ga prepriča, da smrt ni rešitev. Domnevno norega fanta nato prepustijo Jacku v varstvo. Jack na njunih srečanjih posluša fantastične zgodbe o ljubezenskih in drugih pustolovščinah, ki ga čisto prevzamejo. Tako se tudi sam začne zavedati, kako pomembno vlogo igrata ljubezen in strast v vsakodnevnem življenju.
Well-respected psychiatrist Dr. Jack Mickler is only 10 days away from his retirement. A week before he is due to leave, he encounters a young man who attempts suicide--would be a pretty straightforward case except the young man claims to be Don Juan, the fabled Spanish nobleman and world renowned seducer/lover of woman. Despite original hostility from his co-workers, Jack manages to persuade his associates to put the youth in his care for 10 days after which the youth will undergo an evaluation to be either released from psychiatric care or sent to a mental institution. However, as the 10 days progresses, Dr. Mickler and the other staff become gradually drawn into to the young man's exotic world of love, passion and pleasure as he recounts his story to them. Whilst doing so the man's philosophies and zeal for life and love begins to revive Dr. Mickler's somewhat passionless relationship with his wife, Marilyn as well as challenging his own views and ethics to the point where both he and the audience begin to question: could this young man truly be Don Juan?