Recurring
Harris Allan as James "Hunter" Montgomery (seasons 3–5)
Hunter is an HIV-positive teenage hustler who meets Ben and Michael while standing outside their apartment. Ben feels sorry for Hunter and takes him in. Eventually, he and Michael adopt him. Hunter initially has an unrequited crush on Brian but later falls in love with a girl named Callie Leeson.
Sherry Miller as Jennifer Taylor (British version: Caroline O'Neill as Janice Maloney)
Jennifer is Justin's mother and works as a real estate agent. After having difficulty with her son's coming out, with Debbie's help she embraces the fact that her son is gay, joining PFLAG. After divorcing Craig Taylor, she dates a younger man named Tucker (Lucas Bryant) in season 5, much to Justin's disapproval.
Peter MacNeill as Carl Horvath (British version: Dave Nicholls as PC Stroud) (seasons 2–5)
Debbie's boyfriend. He meets Debbie while working on a case involving the murder of a young gay man named Jason Kemp. He is slightly homophobic when Debbie first meets him, but she teaches him to be more accepting of homosexuals. He asks Debbie to marry him and she accepts, but she later decides that she cannot marry Horvath as long as Michael cannot legally marry. Instead, the couple decides to live together in a common-law relationship.
Alec McClure as Chris Hobbs (British version: Ben Maguire as Christian Hobbs) (seasons 1, 2, and 4)
Bully from Justin's school. Justin gives him a hand job early in the series, but he is then revealed to be homophobic. After assaulting Justin with a baseball bat, he is charged with assault and battery and sentenced to community service and probation. He is later shown working in construction, not expressing remorse for his actions until Justin, at Cody's urging, forces him at gunpoint to apologize. Justin plays into Chris's homophobia by claiming that Chris will not report them to the police for fear that people would know he was almost killed by "a couple of sissy fags".
Stephanie Moore as Cynthia (British version: Alison Burrows as Sandra Docherty)
Brian's assistant. Quits Vangard to follow Brian when he starts his own firm, Kinnetic. Charming enough to dazzle clients and firm enough to handle Brian.
Dean Armstrong as Blake Wyzecki (British version: Andrew Lancel as Harvey Black)
A crystal meth addict at the time he meets Ted at Babylon. His relationship with Ted ends quickly after Ted finds out that Blake is still hooked on drugs. In Season 4, he is sober and is Ted's counselor at a rehab clinic. They finally reunite in the series finale.
Makyla Smith as Daphne Chanders (British version: Carla Henry as Donna Clark)
Justin's best friend since high school and the first-person Justin comes out to (not counting Brian or Michael). She asks Justin to take her virginity, since he has experience, and as a result falls in love with him. He quickly turns her down, but they remain friends. Later, they move in together as roommates.
Nancy Anne Sakovich as Leda (season 2)
Melanie's college girlfriend and best friend. She's a biker and, although Lindsay is rather hostile towards her, soon warms up to her. Later on in season 2, Leda helps rejuvenate Melanie's and Lindsay's sex life when it experiences a drought by having a threesome with them but soon grows further attached.
Fabrizio Filippo as Ethan Gold (British version: Jonathon Natynczyk as Dazz Collinson) (seasons 2–3)
Music student at PIFA who romances Justin. Feeling neglected by Brian, Justin leaves him for Ethan. It is a short-lived relationship, however, as Ethan cheats on Justin with a fan. Justin leaves Ethan, who had vowed to be faithful, and reunites with Brian, since Justin had never expected Brian to be faithful.
Matt Battaglia as Drew Boyd (seasons 4–5)
A star quarterback who, although engaged, is a closeted homosexual. He has an affair with Emmett and later leaves his wife to be with him, although they do not stay together. Drew comes out to the media with a controversial on-air kiss with Emmett.
David Gianopoulos as PC Jim Stockwell (season 3)
A mayoral candidate with Brian as head of his ad campaign. Stockwell is a homophobic police officer who abuses his authority. Initially, Brian helps with the campaign, but at a certain point he decides to sabotage the campaign with Justin's help, as Stockwell is closing the gay nightclubs. Brian launches a smear campaign, and as a result Stockwell loses the election and is indicted.
Carlo Rota as Gardner Vance (seasons 2–4)
Brian's senior partner at the advertising agency. He buys Ryder's from the previous owner and christens it Vangard, firing every single ad exec but Brian—who proves himself indispensable by going after and signing up the Brown Athletics account that Vance had been after for years. Brian becomes a partner after this and continues to be until the Stockwell smear campaign in season 3, which results in his getting fired.
Robin Thomas as Sam Auerbach (season 4)
A renowned artist who is notoriously difficult to deal with. He is instantly attracted to Lindsay and pursues her even though she is a lesbian. After his Pittsburgh art exhibit (which Lindsay organized), Lindsay gives in and they have a brief tryst at the gallery.
Mitch Morris as Cody Bell (season 4)
Leads the "pink posse" and convinces Justin to join.
Lindsey Connell as Tracey (British version: Caroline Pegg as Rosalie Cotter) (seasons 1–3)
Worked with Michael at the Big Q. She had strong feelings for him and was devastated to find out that he was gay but eventually remained his friend. After Michael left the Big Q to start his comic book store, Tracey made several appearances, including when Ted interviews for the store's assistant bookkeeper position in season 3.
Meredith Henderson as Callie Leeson (seasons 4–5)
Hunter's high school friend and at one point his girlfriend. When she finds out that he has two fathers and is HIV positive, she is surprisingly not worried. Her parents embarrass Hunter at a swim meet when he hits his head in the pool and begins to bleed. When Callie rushes to the pool to help him, her father shouts that he "has AIDS". The entire room hears, and soon the entire school knows. Callie remains a friend of Hunter and appears occasionally through the remainder of the series.
Mike Shara as Brett Keller (seasons 4–5)
Hollywood movie producer who offers to produce a movie version of Rage.
Rosie O'Donnell as Loretta Pye (season 5)
Deb's replacement after she quits the diner so that she and Carl may spend more time together. Loretta applies for the job with no prior experience but convinces Deb to hire her when she tells Deb that she was kicked out of her house by her abusive husband because he caught her making out with her best friend, a woman. After Loretta works at the diner for a couple of weeks, her husband comes to take her home. When she refuses, he tries to drag her out, but Deb comes to the rescue, threatening him with a baseball bat. Afterward, Loretta and Deb become friends, but things go awry when Loretta kisses Deb while they are out for drinks. Deb eventually lets Loretta down gently, and Loretta decides to leave town, saying that she loves Deb too much to be anywhere near her.