Jupiter in the 1st House

The 1^st house is the house of "Self".  It is home to our ascendant/rising sign and is associated with self-image, our style of initiating things, and how others notice us in a first impression or superficial setting.  It is the house through which we consciously perceive the world and how it perceives us.  Any planetary placement within the First House will be more pronounced in the personality of the individual.

With Jupiter, the planet of luck and expansion, being in your first house, you are relatively lucky, generous, jovial, optimistic, cheerful, confident, well-intentioned, and have robust vitality.

You probably like outdoor sports and are good at them.  This placement brings many opportunities for personal growth and expansion, including a potential weight problem.  

Your confidence in yourself makes you a good leader and promoter because you have the warmth and sociability to inspire faith and trust in others.

Depending on how Jupiter is aspected, you can, however, be extravagant, gullible, over-emotional, egotistical, or self-indulgent.