I am looking for a single English word which describes the mental quality of being not content with small achievement, but working hard to achieve higher level. For example, an artist who is not satisfied with winning a prize or fame, but focusing on his art of work and trying to discover a new way of impression and inspiration in his work.
Ambitious, career-minded, hustling, driven, hard-charging.
having a strong desire for personal achievement
definition via Merriam-Webster Online.
How about persevering, conscientious, perfectionist, driven.
Try avaricious; it’s usually asociated with a desire that extends beyond simple greed but can be used to describe an extreme greed for success, power, or recognition.