Early LifePenelope Johnson was born to Gordon Johnson and P. Baxter on June 23rd 1930. Penny grew up in the Halliwell Manor with her parents until her mother, P. Baxter died in December 1970 Penny married Allen Halliwell and took his last name and gave birth to Patricia Halliwell on April 5th 1950. Penny's husband Allen led Penny "down the hippy dippy trail" as she put it, and made her a flower child. Penny started to shun her wiccan duties and believed that killing creatures of any kind is still murder, even if they're demons. But when Penny's friend Robin (a secret warlock) killed her husband Allen she vanquished Robin and her boyfriend Nigel (a warlock). After the death of her first husband Penny became very rigid and vanquishing demons became her life. Sometime after these events Penny went to college, joined a sorority, met her best friend Gail Altman, and remarried three other unknown husbands.
Raising the Girls and DeathAfter the death of her daughter, Patty Halliwell, Penny took away the girls magic powers, and fought with her son-in-law, Victor Halliwell, about who should raise the girls. But when Penny brought up the fact that Victor couldn't protect the girls from demon attacks Victor left town with his pride woundedWhen the girls were at a young age Penny Halliwell started a coven of witches that was based out of her home, and consist of Gail Altman, one of her old sorority sistersPenny raised the girls as if they were her own, but didn't tell them about their magical powers. Penny had a seemingly easy time raising the girls, except for Phoebe who had a rebellious personality. After the girls graduated high school they moved out of Halliwell Manor. Piper and Prue moved into an apartment together in San Francisco, and Phoebe went to New York City to look for the girls father.
Penny became ill sometime after the girls moved out. When Penny became ill Prue and Piper moved back into the Halliwell Manor, but Phoebe chose to stay in New York City. Sometime in 1997 or 1998 Penny died and Prue, Piper, and Phoebe received their powers
AfterlifeAfter her death Penny helped the girls fight demons as a ghost from time to time. At first in seasons one and two Penny only really helped the girls by magically turning pages in the Book of Shadows to give the girls hints. In season three episode two 'Magic Hour' Grams summons herself magically as a ghost and gives Phoebe advice about accepting Piper and Leo's relationship. Later in the episode Grams attempts to do a Hand Fasting Ceremony for Piper and Leo, since she is a high priestess, but she can't because Leo is orbed out by the Elders (an elder group of whitelighters who train and advice whitelighters).
Throughout the next seasons Grams helps the girls many times by appearing as a ghost.
Powers During her appearances the only power Penny displayed was that of telekinesis. She was very experienced at the use of her power, something that Prue herself acknowledged when Penny moved her and her sisters out of the manor, thinking that they were warlocks. She was also very good at creating spells and potions, having created a lot of them during her lifetime. Back in her younger days, or the " Summer of Love " in particular, she only used her powers in the act of love. However, after the death of her husband and the danger her future granddaughter went through, Penny used her powerful and skillful telekinesis to kill the demon, then went to her common self to fight demons in the spirit of good.