Preston, nicknamed PJ, has a lot of money, and he's in business with Annie. She wants to spend her money for charity, and convinces PJ to help her.
In No Good Deed, he disguised himself as a waiter and talked to Annie. He said that he "heard that Hillingsbrook guy is a real tool". At the end of the episode Annie went to his boat and started to shout at him, not realizing that the man she was shouting with was not Preston, but the captain of the boat. She then turned around to find Preston right behind her, who teased her by recalling the last time they met, when Annie called him a tool.
In Babes In Toyland, Annie went to Preston's house, where she found him playing a game called wine balloon archery. Preston said that Annie is uncomfortable with wealth, and that is why he does not want to work with her. She said if he changed his mind let her know. Later Annie and Preston met in a boutique, and Preston told her that he would do her project with one condition, because he can't work with someone won's going to make him guilty about his money, he wanted her to spontaneously make a purchase without caring about the price or demonstrating any discomfort with spending a large sum of money.
"I want you to buy something." - he said. "That's all? Listen PJ, I went to West Beverly High, I can shop." - she replied. When Preston told her to buy something big, something she always wanted, but she could never afford, Annie picked a nina bag, which in the end Preston bought for her. When she came home Jen recognized that the bag is a really expensive one. She later found out that the bag cost about $40,000 and brought it back to PJ. The next day he told Annie that "6 years ago, he tried to start a magazine. It was a very cutting-edge, brainy, politically-minded thing, and it could not have been a bigger flop. His mother called it the Dilettante Monthly He had been afraid to be involved with anything since until her project came along. He said he was going to help her, not only to help, but to also ensure that her project wasn't a complete failure like his. In the end of the episode, Preston met Naomi, and they had a connection.
In Blood Is Thicker Than Mud, Jen asked a prophetess, Sybil, what she can see about her "mystery man". Naomi asked her too about what is going to happen between PJ and her. She said: "I see a broken heart
from the one you love most." - Naomi believed that she was taking about PJ, so she didn't believe her. But in the end of the episode, when Naomi thought that she and Jen are OK, she found a letter from Jen. She wrote that she went to Napa Valley with Jacques to relax, but that means that she went after Preston, who went there to help his father. Naomi learned that her sister doesn't care about her at all.
In The Heart Will Go On, early on in the episode Preston was a bit confused because none of the girls in the house were flirting with him anymore. Annie told him what happened so he decided to do something for Naomi. Naomi told PJ, that Jen was her only sister, and now she lost her. Then, PJ kissed Naomi and they slept together. It was after they slept together that Jen called Naomi about a secret regarding Preston.
In Blue Ivy, Naomi asked Preston, what his secret was, but he didn't answer. When he texted Naomi that he couldn't go to the couple massage, she followed him. She saw him receive a box. But she was caught and therefore asked by Preston to open the box. There were Cuban Cigars in it. He was mad at her for following him and left. Naomi, in a desperate attempt to make amends, asked Annie to talk to PJ. After Annie told him the check he wrote for their charity fundraiser bounced, he explained that he could not access the rest of his money unless he gets married by 28. He asked Annie not to tell Naomi about it because he really loves her, and did not want her to think that he was only marrying her to get all of his money. Annie lied to Naomi, but by the time she decided she wanted to tell Naomi the truth about Preston, it was too late. Preston had already proposed to Naomi. Annie soon tells Naomi the truth, but decided that she and Preston belong together and that they are truly in love. Naomi eventually calls off the engagement realizing that Preston is only in it for the money and not because he loved her.
In 'Tis Pity It is later revealed that Preston got married to another woman.