If we define career as a deliberately planned machine, a means of securing and improving our material needs, then success may be simply defined as maximizing remuneration to the greatest extent possible with the tools at hand. The wealth generated allows us to realize personal needs and goals beyond subsistence.
I do not mean to imply a simply mercenary aspect in this description, altruistic goals can also be indulged either through your career choice directly, or through the resources that it can generate. Perhaps a successful career is one that enables choices (free time, security) and does not dominate our personal lives.
If we are discussing a vocation, something we are compelled to do for whatever reason, success may be defined differently. As part of a continuing craft tradition, I am constantly learning from the past to preserve and develop knowledge. Hand-in-hand with this is the obligation to share what I have gathered with others; I am a custodian of my craft, I am a temporary vehicle for knowledge and skills that need to be handed off carefully as they were imparted to me. There is a further obligation to the careful utilization of the raw materials needed for my work, in terms of extraction, use and disposal. If things go well my craft will reward me with what I consider a decent living. If things turn sour, then it is best that I bow out of the arena rather than do work that might demean or cheat craft standards. Vocation is a tricky path to navigate not the least for a partner or children of those who choose it. There can certainly be a lot of personal satisfaction, without the usual socially accepted hallmarks of "success".