He is a very powerful and ruthless being, the son of King Cold. He is involved in the planet trading business. Planet traders send their minion to hospitible planets, who then wipe out the current inhabitants in order to prepare the planet for sale.
Being so powerful, he invokes a lot of fear in many. He was born as one of the most powerful creatures in the universe, and never developed feelings of empathy or love for anyone.
Frieza hears of the dragon balls and their power, so travels to the Planet Namek to try and obtain them. He uses his workforce to terrorise the Namekian population into telling him where the dragon balls are. He does not have the ability to sense power levels, so uses a scanner to detect power sources. Two of Frieza's 'right-hand men' are Zarbon and Dodoria.
Frieza is usually in a low-power state, and uses a floating chair to move around. He can transform numerous times, into a much stronger being. Frieza is chopped in to several pieces when his own attack against the Super Saiyan Goku backfires. He is then blown up in the destruction of Planet Namek.
Frieza's mangled form was found in the planet debris afterwards by his father King Cold, who then had his workers construct mechanical replacements for Frieza's missing limbs. Once he was resurrected by his father, Frieza swore vengeance on the Saiyan who defeated him, and headed for Earth. Upon reaching earth however, he was killed by the Halfbreed Saiyan Trunks.