Leo was sent to the Halliwells by the elders, but since he couldn't tell the sisters, he posed as a handyman. Both Piper and Phoebe showed intrest in Leo, and it soon became a competiton for his attention. After Prue cast the truth spell, Piper took the oppertunity to make a pass at Leo, and after asking him how he liked girls who made the first move, Piper bodly kissed him. When Leo became too close to Piper, he had to leave the sisters. After getting shot by a darklighter, Leo orbed himelf to the manor, where the sisters were about to leave for a vacation. Piper was shocked and angry at the revelation of Leo being magical. Piper then successfully heals Leo by switching their powers. Afterwards, Leo leaves the Halliwells to go back to the heavens, and their relationship is seemingly over.
With Leo gone, Piper becomes involved with her neighbor Dan. After Piper gets sick with Oroya Fever, Leo goes behind the Elders backs to heal Piper. Leo subsequently temporarily looses his powers as a punishment, and Piper gives him a job and place to stay at P3. On Valentines Day, Leo gives Piper a card and flowers, and Piper has a daydream about running to kiss Leo, but she doesn't act on these feelings. It is later revealed their past lives were having an affair. Piper struggles with choosing between Leo and Dan, and after a spell goes awry, she reveals she loves Leo, and doesn't need a spell to tell her that.