Debi Mazar's recurring role of Shauna in season 1 becomes a regular role in season 2. Mazar makes her final regular appearance in episode 42. When she made appearances in seasons 4 and 5, Mazar was credited as a special guest star. Perrey Reeves (Mrs. Gold) and Rex Lee (Lloyd) had recurring roles in the first two seasons. Starting in season three, Reeves and Lee joined the supporting cast of the show and were credited as "starring" in the end credits in the episodes that they appeared in. After Debi Mazar left on maternity leave, Reeves began to receive in the opening credits starting in season 4 replacing Mazar's credit, and is now credited whether she appears in the episode or not. Rex Lee's name also now appears in the opening credits as of season 5 whether he appears in the episode or not.

Rhys Coiro's recurring character Billy Walsh was given a bigger role in the storyline, and Coiro was credited as "starring" in the first six episodes of the season. However, when his character returned in episode 52, he again was credited as a guest star.

Ari's long-suffering assistant. Lloyd Lee is a gay Chinese American who holds an art history degree from Sarah Lawrence College as well as an MBA from Stanford Business School. As Ari's assistant, he is subject to a demanding and verbally abusive boss and his sexual orientation and ethnicity often fuel Ari's venomous barbs, which seems to later harden Lloyd into becoming an agent. Lloyd considers E the "only nice person" in Los Angeles. He remains loyal to Ari when he is terminated, and delivers a motivating speech to Ari following the incident, which inspires him to start up his own agency. Although Ari continually verbally abuses Lloyd, he cares a great deal for him as Lloyd repeatedly proves himself as Ari's best assistant. Ari goes out of his way to help Lloyd on two episodes: Ari goes to a gay bar and saves Lloyd from a gay TV show writer played by Will Sasso who is looking to take advantage of Lloyd; Ari reunites Lloyd with his boyfriend after a relationship breakup. In season 3, Lloyd booked Johnny Drama an audition in an Edward Burns' TV pilot and is his current agent. In the Season 4 finale, Lloyd and his boyfriend Tom go on a Rosie Cruise, which can be seen in the background of Ari and Lloyd's phone conversations. It is revealed in Season 4 that he has a picture of Ari being used as his personal dart board, probably for all the times Ari makes fun of him. Also in Season 4, it is revealed that his family is wealthy after Ari visits Lloyd and finds him living in an upscale condominium. In season 5 title credits, Lloyd is credited as a main character. In the season 6 premiere, an infuriated Lloyd holds a power play over Ari when he demands a promotion after being Ari's assistant for 3 years. Upon witnessing Lloyd demand Ari promote him to agent, Ari's colleague Andrew Klein even refers to Lloyd as a "tough queer". Andrew later appraises Lloyd over his power play when Lloyd manages to get Ari's family to side with him by saying "This kid's gonna get far in this business." Lloyd's demands are partially influenced by a conversation Lloyd has with his father, who is revealed to own a winery in Napa Valley. Ari makes a deal with Lloyd that if he does everything Ari asks within the next 100 days, Ari will consider promoting Lloyd. Lloyd is forced to lose fifteen pounds as well as perform other strict tasks. On "Lloyd's Diary" on HBO.com, he reveals his last name to be Lee. Since season 3's Three's Company Lloyd has been the agent ("half-agent") of Drama. In Season 6's 'Security Briefs', Lloyd quits MGA and thinks about taking a 3 year agent position deal at Adam Davies and Terrence's agency, which is offered by Davies personally over the phone. Lloyd is given a warm welcome by Davies and his first order of business is to help get Drama off "Five Towns" and onto the new Melrose Place. Lloyd is temporarily replaced by Ari as Drama's agent when Ari uses his connections to get Dan Coakley a country club membership in exchange for taking Drama off Five Towns. However, when Drama sees that Lloyd sees more potential in him than Ari, Drama signs with Lloyd. This is in particular when Lloyd confronts Drama and tells him that he's watched every project Drama has been cast. When Ari buys out Terrence's agency, he offers Lloyd to come back. Lloyd pays Ari a visit to tell him that he won't work for him again after being abused for so long. Ari surprises him by officially making him an agent. Played by Rex Lee (64 Episodes)

Ari's long-suffering wife and the mother of his children. She is strong enough to stand up to Ari's intimidating personality, and is in charge of the homestead. Former soap actress, now a tennis-playing Beverly Hills socialite. In season 3, it is revealed that Mrs. Ari has a sizable trust fund into which her husband has been dipping to start his new talent agency. Season 3 also revealed that Ari met his wife as an undergraduate at Harvard, when he was a member of Zeta Beta Tau, a traditionally Jewish fraternity. Mrs. Ari is a recurring guest star in the first 3 seasons and a credited star in the intro of Season 4. Creator/Producer/Head Writer Doug Ellin has stated the change in the introduction credits is the work of HBO. In season 4, it is revealed that Mrs. Ari played "Kendall Scott" on the soap opera The Young and the Restless, when the producer of Y&R calls her for a one-day arc comeback. She was then offered a full-time role, but turns it down stating that she left acting at age 25 because she wanted a family. Ellin has stated in many interviews and on various DVD commentaries that Mrs. Ari will never get a first name in the show. In season five, it is revealed that Mrs. Ari did an erotic film that Ari tried to hide, but Adam Davies posted a picture from the film on the web. She later tells Ari that he has to make the decision of whether he wants to be studio head of Warner Brothers on his own. She tries to find out from Ari if Andrew is cheating on his wife Marlo. Though Ari denies that Andrew is cheating, she later finds that he was lying. She eventually forgives Ari for lying after he tells her he will never lie about any friend of his who is cheating. She later refuses to allow Ari to use her money to buy out Terrence's agency because she believes he wants revenge. Ari admits his hatred for Terrence, Davies, and Lloyd, but insists that buying out the agency is all about business, and she agrees to allow Ari to use her money. Played by Perrey Reeves (58 Episodes)

Vince's publicist, who describes herself as Vince's "West-Coast mother", is a brutally honest woman who speaks her mind to Vince and the boys. Shauna is a recurring guest star in Season 1 and a star in Season 2, 3 and 4. At the beginning of season 3, Shauna is pregnant but is still working as a publicist for Vince. In Season 3 season finale we find out her child is a girl, but in season 4 Gary's Desk episode we find out its now a boy as she asks her assistant where is her son. Creator/Producer/Head Writer Doug Ellin has stated the change in the introduction credits is the work of HBO.[citation needed] In season 5 she gets Vincent a job to do an appearance at a sweet sixteen party in which he will be paid $200k which would prevent Vince from having to declare chapter 11 bankruptcy. She needed help from Marvin to convince Eric and Vincent to take the appearance job. She helps Vincent during his Jay Leno appearance in the season 6 premier. Played by Debi Mazar. (36 Episodes)

Terrance's daughter, with whom Eric was romantically involved in seasons 2 and 3. At the beginning of season 4, Eric said that he and Sloan are "taking a break". In the middle of Season 4, it is shown that they actually broke up in the season 3 episode. Sloan reappears in season 5 after Seth Green gives Eric an ultimatum with regards to starring in his client's TV show. Eric must convince Sloan to call Seth and ask him to do the show or else he would refuse. Sloan is initially taken aback by the request and refuses, as she also hates Seth Green for stalking her following a Teen Tour several years back. However, as Eric is leaving, she realizes that his situation is desperate and agrees to make the call if Eric really wants. It is also revealed that Sloan may still have feelings for Eric following their parting discussion about them both being single. In season 6 Sloan convinces E to rent her friend's house. E later admits during "The Great Gatsby" premier after party he still wants a relationship with her, and she states she just wants to be friends. But, can't be at this point until he gets over her. During a charity golf game she is co-chairing, she informs her godfather Murray Berensen about E and Murray offers E a job. E turns down Murray's job offer initially after hearing about it, but reconsiders it after breaking up with Ashley. He calls to apologize to Sloan after getting the job and asks her out for a drink, but after learning Sloan has a new boyfriend and getting a call from Ashley, E decides they can no longer spend time together until Sloan can decide what she wants from their relationship. In the Season 6 finale, Eric takes Sloan to lunch, and after a long argument, reveals his intent to marry her, and proposes to her. She accepts, and now Eric and Sloan are engaged. Played by Emmanuelle Chriqui. (21 Episodes)

Mandy Moore's agent and former mentor to Ari Gold. Shortly after Ari's departure from Terrance's agency, Barbara offers him money as part of a joint partnership to create their own agency now known as the Miller-Gold Agency. The agency is a 50/50 partnership in which both partners need to agree on a firing and a hiring. In season 5 she offers Ari 10 cents per every dollar he invested in the MGA agency should he take the Warner Brothers Studio head position. After Ari doesn't take the studio head job, she is told by Ari that he wants to expand their agency, something Babara has wanted to do for some time.

Ari informs Barbara that he is buying out his friend, Andrew Klein's Klein-Cutler Talent Agency. Klein-Cutler has five agents, 65 profitable clients and made $5 million the year before. Barbara likes those numbers, but doesn't believe Klein is big time agent material. Because of this, she refuses to agree to the buyout, which she is allowed to do under their partnership contract. Barbara eventually agrees to meet with Andrew Klein. However, during the meeting, Barbara causes Klein have a panic attack, making Barbara say no to hiring Klein and merging Klein's agency with theirs. Barbara says that Klein reminds her of her second loser husband.

In the end Barbara agrees to hire Klein as long as Ari keeps Klein on his side of the agency and is kept under his name for paychecks. She agrees only because Ari comes to her award ceremony and ruins it by embarrassing her. Ari also threatens to split their company down the middle. Barbara tries to make him apologize at the ceremony, but Ari makes a crass comment instead and leaves.

In season 6, Barbara wants to fire Klein after she sees him walking around the agency in his robe. She tells Ari if Aaron Sorkin is not signed by Klein by the day's end Klein will be fired by her or Ari. She, Ari and Lizzie end up taking the meeting with Sorkin after Klein ends up in jail, in which Sorkin admits he still hates her, indicating she was once his agent before. Played by Beverly D'Angelo. (17 Episodes)