Lady Leia, Princess and Ambassador of Alderaan, had a fiery personality and sharp intellect that made her an influential diplomat. Her speeches and public image were instrumental in generating sympathy for the rebel cause. Using her diplomatic connections to gain access to highly guarded information and smuggle supplies, she was an integral member of the Resistance.
As a child she was adored by the public, a symbol of hope in a troubled time. However, as a teenager she suddenly withdrew from the public spotlight and joined the military. This withdrawal coincided with the unprecedented Imperial closure of a popular musical (Gilbert & Snootles' HMS Executor, a comic opera that was highly critical of the Empire), an act of censorship which drew much ire from the people of Alderaan.
After two years in the service, she had become an adept marksman and had even led a number of peacekeeping missions in Rodian territories. It is believed that it was during this time that she joined the Resistance, and may have even had a hand in organizing it into the significant force it became.
With the destruction of Alderaan, Lady Leia became not only an important member of the Resistance, but once again she became a symbol of hope and a powerful reminder of the Empire's atrocities.