Grissom was a Gamorrean with a strong sense of honor and a noble character.
Over the course of his life, Grissom saw most of his Gamorrean friends slaughtered in battle, and wore several long scars along the left side of his face. Later, his wife and daughter fell victim to a fatal disease, and he cradled both in his arms as they died. Having lost his family, Grissom pursued a mercenary career and was employed by Jabba Desilijic Tiure for a time.
When Jabba was killed during Luke Skywalker's rescue of Han Solo, Grissom once more found himself alone and without purpose. For some time, he traveled the galaxy, taking whatever job he could get, and eventually ended up working as a pitfighter on the planet of Otunia. One evening in the local cantina, a Gran, who was harassing a young Human female named Arista Kabul, caused Grissom to spill his drink. Though Grissom ignored the intrusion, the Gran subsequently provoked him, and Grissom's frustrations boiled over. Grissom knocked out the Gran, starting a bar fight. Grissom was arrested by the local security and forced into working at Arista's influential father's quarry.
A week after that incident, Arista's uncle Seth Kabul, who had made an alliance with the foundering Galactic Empire, attempted to assassinate Arista's father by planting a powerful explosive device in the quarry, set to explode during Lord Kabul's inspection rounds. Grissom survived the explosion and saved Arista's life. Her father, mortally injured, asked Grissom to protect Arista and help her get off planet. Cradling an unconscious Arista in his arms, Grissom's recalled how helpless he felt when his daughter died in his arms years back.
Assisted by a Jawa named Tek, Grissom and Arista eventually managed to sabotage Seth's operation and escape from the planet. In the unlikely trio, Grissom's life once more gained a purpose, and Grissom himself gained two invaluable friends.