Fred is an angel who was in charge of Deb's case when she arrived in heaven. When Deb went back to Earth, he was demoted to the position of a guardian angel. To keep an eye on Jane, he starts working as a mail clerk at her work.
Little is known of Fred's life before he met Deb. He worked for "the man upstairs" for a while and was a gatekeeper and later described his former boss as a control freak.
Fred is the angel who was in charge of Deb's case when she was alive. After she died, he was demoted to being her guardian angel and works as a mail clerk in the firm. Still getting used to being among humans, he's struck by the attraction he feels toward Stacy. He ends up kissing her and they seem to go out together but the next day Stacy claims to have no idea who he is. He leaves a note to Deb explaining that he ended up breaking rules with the kiss and was thus reassigned with all memories of him erased, except from Deb's mind. He returns a few episodes later, revealing he couldn't maintain his job because of his feelings for Stacy and thus gave up being an angel and took human form to return to Earth. However, he realized he was too focused on Stacy and told Deb/Jane he was leaving to travel the world and learn more about being human.
Unfortunately, Fred can still be recalled to Heaven even if he is human because he still has to keep an eye on Deb/Jane. He returned, claiming to have been traveling the world but later admitted he'd never left Los Angeles as he's been assigned back to looking over Deb/Jane. He soon gets a new job as Kim's assistant, although his desk is actually facing Jane's office so he can keep a eye on her. Eventually, he and Stacy started dating.
Fred and Stacy were already a couple, but she breaks up with him to date her TV series co-star. He intends to propose but when he hears from Jane that Stacy kissed Grayson, he is heartbroken. Jane encourages him to go on his own and enjoy the world.
It has been confirmed that Jane will have a new guardian angel in the fourth season. Fred will most likely appear in the coming season, but it is still unknown when and what kind of a role he will play as the series continues.  It was also confirmed that the real Jane confronted Fred and tricked him into telling her how to get back her own body from Deb.
Fred appears in the Season 6 episode No Return and is the gatekeeper for Grayson Kent. He helps Grayson return to Earth by getting the one remaining keyboard with a return button but warns Grayson that since the keyboard is the only one with a return button, Grayson will only get one chance.
Fred first met Deb when she went into heaven, he pointed out that she hasn't done any good or bad deeds and had labeled her "shallow". She was insulted and press the return button on his computer in an attempt to return to her own body. Instead, Deb woke up as Jane and Fred was punished for it by having him demoted as her guardian angel.
When Deb began her life as Jane, Fred was demoted to the position of a Guardian Angel. Since then, he has been Jane's mentor, working at H&P either as temp or an assistant so he could keep an eye on her.
In Season 4 after returning to Heaven, Fred was confronted by the spirit of the true Jane, whom was very disgusted and upset with what Deb did with her body. During cross examination, she found out a way to get back to Earth so she can take back her life. Against Fred's wishes for Jane to leave, she outmaneuvers him and presses the return button.
Fred is Kim's assistant in season 2. The only reason he takes the job is because it is across from Jane's office so he can keep and eye on Jane.
Fred became romantically active with Stacy from Season 2-4. After trying many things to get Stacy fall for him, they finally have a moment by the end of season 1. When they kiss it breaks the guardian angel rules. He is sent back to heaven, and Stacy does not remember him. He later comes back and he and Stacy continue their relationship. In Season 3, Stacy becomes uncomfortable because instead of sex, there is too much kissing. Later her and Fred have sex for the first time. Stacy gets a job in a cop show. She later becomes a diva and cheats on Fred with a co-star. They break up and Fred is heartbroken. After Stacy realized that her co-star was a jerk and sleeping with her assistant she slaps him and goes to jail. Grayson later bails her out and kisses Stacy at his office and Jane sees and tells Fred. Fred was crushed because he was going to propose to Stacy. He goes to the airport and plans on taking a trip to Iowa. However, he meets his future girlfriend and never makes it on the plane. Later in Season 4, Stacy confesses she still loves Fred and walks away with tears forming. He was asked by his girlfriend if he still had feelings for her but hesitated. He was dumped and went back to Stacy so they could be together, however she says no. So without anybody to love he confesses his guardian angel status. Stacy apologizes and says she wants to be back with Fred, but it's too late. They share a passionate kiss and he walks out the door and Stacy loses her memory of him. He later meets Jane at the courthouse and thanks her for pushing the return button and showing him what it's like to be human. He is interrupted by Owen. When Jane turns around he is gone and sent back to heaven.