June is the daughter of Lt. Ezra J. Hammer USN and Prof. May Hammer (nee’ Campbell). Her father was a Navy pilot who died when his plane crashed. While all the Hammer Sisters inherited their parents' super genius level intellect, June is the only one to have her father’s red hair. Her mother, May was a noted college professor and super scientist who put June on her future path, though she disapproved of her daughter’s controversial theories. June grew up in the same Jersey Shore town as John, where she demonstrated that she was very intelligent, athletic, and naturally talented at almost anything she tried. She went to St. Christopher’s Catholic High School, where she met a young John Nash who was in trouble for fighting. The two became fast friends and shared in many adventures. Through most of High School they had an mutual but unspoken crush on eachother, though this was often frustrated by John’s relationship with the vampire hunter Alex Knight and jealousy over June’s relationship with Max West, leader of St. Christopher’s Big 4. This crush was consummated before the end of their senior year after John revealed to her his alien heritage. The two went to college together and continued their relationship, but it came to an end when John’s parents died in a car accident and he vanished. Heartbroken, June nonetheless completed college, entering the science field though she also became a popular science fiction author on the side. After several years, John showed up on her doorstep again seeking to reconcile.
June is characterized by her fiery temper and “can do” attitude. She also has a very competitive personality and accepts without hesitation any challenge that crosses her, regardless of difficulty or time constraint. Her constant optimism and over-confidence makes her seem arrogant. She has very high standards and won't accept anything less than perfection from herself. Her drive and purpose give her a tendency to have tunnel vision when it comes to a task, and the intensity with which she pursues her goals tend to spook John, who is more of a slacker. When she gets into such a frame of mind he calls her “The Woman Made of Fire.” June has a very slender figure with large breasts, and has a tattoo of a heart and crossbones on her lower back. She is very athletic, but is conversely very clumsy. While in space during the Crash campaign, June was inoculated with the Athanasia Serums, which protect her from most galactic diseases and keep her from aging. Despite not generally being counted as a member of the Magnificent 7 because of her lack of combat strength, it was June who coined the name for the group and who holds the most authority aboard the Rocco II, notably being the only one to successfully boss Cain around. June fulfills a variety of roles aboard the ship, including co-pilot (she actually pilots the ship more often than John does), navigator, and engineer. She also occasionally takes care of cooking, and Cain regularly says he likes her cooking better than Thuro’s. June also handles the group’s money, and is generally in charge of getting supplies. It is generally left to June as well to make sure the others aren’t slacking in their chores of upkeep around the ship. Much to her chagrin she even needs to remind John to work, and is often yelling at him about the rashness of his decisions alongside the ship’s AI, Rocco.
- June's actual first name is Valerie, which her mother still calls her. June explained that as a child she had a best friend also named Valerie and decided to go by June herself which she thought was a prettier name.
- June has a fondness for socks and is almost never not wearing them. She likes even wearing them to bed. When the group vacationed on Tyre and she was whisked away to Zion, she blamed her bad luck during that adventure on the fact that she wasn't wearing socks.
- June has a tattoo on her lower back of a heart and crossbones and a pierced belly button.
- June's official job is that she's a professor at Chapel University in Philadelphia, where both she and John went to college. However, she rarely teaches classes and is often left alone to her research. She is a famous name in the super science circles and the University generally keeps her on the payroll for her name. June is prone to long absences from work for which she never gets in trouble. It was for this reason that she was able to head off into space with John without worry.
- A defining moment in June's and John's relationship was "the night in the cave." During this John and June became trapped in a mine where a mysterious energy source was befuddling John's Aura sense so he couldn't immediately find their way out. Falling through a collapsed tunnel into an underground lake, John rescued June and brought them over to a rock outcropping where he advised her stripping out of her wet clothes so she didn't freeze (this was before he revealed himself as an alien and followed suit so as not to raise her suspicion that he didn't need to worry about that). June agreed but warned John not to look at her. While changing, she got a look at him and became immediately attracted to his chiseled physique which he explained as the result of his father's martial arts training. This marked the evolution of June's attraction to John from one over their shared interests to an intense physical one. It was also on this occasion that John revealed to June that he was an alien, something he hadn't even told his girlfriend Alex Knight at that point and also the first time she and John had sex. Afterwards both tried to act like nothing had happened, but it was too late.
- She has admitted since to Kara that while she regularly gives John a hard time about what a lazy slob he is, she is extremely physically attracted to him and tends to fall into giggly excitement at the idea of getting him naked.
- St. Christopher's gathered people with either extraordinary physical powers or mental abilities, and June was noted as having a super genius intellect and was a brilliant strategist. John has said numerous times that her brain can move even faster than his. Every member of the Magnificent 7 has since repeated that she is the fastest thinker among them.
- Because of her time under Max West's mind control, June is somewhat weak against telepathic attacks. Much to her annoyance and embarrassment, she falls under the influence of psychics rather easily, though in most cases she is able to break free relatively quick. She has proven especially vulnerable to the charm powers of vampires, though John privately believes this is due to a vampire fetish June has had since they were young.
- June is extremely clumsy, and is prone to tripping or falling often. She possesses no combat ability at all, but simulatenously has a talent for completely avoiding being injured or killed no matter how powerful the opponent.
- June was something of an outcast in High School, as she was not a strong martial artist and her supergenius level intellect made interacting with other students difficult. When the popular Max West became infatuated with her and pursued her she thought he was trying to have fun at her expense and blew him off. Over time though he wore her down, and she was surprised that he seemed far more thoughtful and kind than she'd earlier believed. She came to believe that the cocksure popular boy she disliked was only a mask, never suspecting that the boy she was falling in love with was merely another mask. While they had practically nothing in common, June enjoyed being wanted by a guy of Max's status. Max on the other hand cared little for her personality and cheated on her regularly, but was enthralled by her "shiny mind" (his powers were psychic and he was drawn to June's powerful intellect) and incredible beauty. He would jealously guard her from other guys and regarded her as his prized possession. Later June met John, who she bonded with through mutual interests and their shared passion for things Max considered dorky and was dismissive about. This friendship eventually blossomed into love, though neither was initially willing to act on it. June was unwilling to cheat on Max and John would get annoyed whenever she brought her long distance boyfriend up in conversation. Neither realized that her doing this was a defense mechanism to avoid dealing with her growing feelings for John. When he began dating the vampire hunter Alex Knight, June got extremely jealous.
- After John broke up with June fell into a months long spiral of recreational drugs and casual sex where in her own words she "took anything and fucked anyone she could to avoid dealing with how she felt." She feels a great deal of shame for how far she fell during this time, and at the tail end of it she met a straight laced and deeply religious man called Brad Thorne and got into a serious relationship with him. After dating for a few years he proposed marriage and she said yes, and it was at this time that John looked in on her. Upon seeing her current situation he decided he'd missed his window with her and not long after left Earth with Dashora and Thuro. While he was gone, June's engagement fell apart.
- June's nickname for John is Chicken. She has, to date, refused to explain WHY she calls him that.
- June has a burning thirst to understand things, though the way she goes about it is more intellectual than intuitive. She has an obsessive need to figure out the nuts and bolts of the way things work and greatly enjoys doing the math required to do so. She is also highly ambitious and willing to do anything in order to achieve her goals and can become surprisingly ruthless in the process. This trait has long been a source of fear for John and caused Cain to greatly respect her.
- While he tried to hide it from her, June eventually discovered that John and Kara had slept together and they got into a heated fight over the matter. June told John that they needed a break and disappeared from the Garage for a few days, over which time she hooked up with the legendary adventurer Patrick. Patrick gave June advice on how to get over her anger at John and advised her to go back to him. When she returned she told John she decided to forgive him and when John caught Patrick's scent on June, he angrily decided that they were now even.
- While they quickly became great friends, June was occasionally startled with how cuddly Kara can be, and on more than one occasion had to remind her that she's not into women. Despite this, she has been seduced by Kara a number of times (as she's said, "Kara has a way of making it impossible to not want to fuck her,") to the point where she no longer holds John responsible for having slept with Kara in the past.
- Since her youth, June has been a rabid fan of comics and cartoons. She taught herself Japanese as a child in order to read her favorite comics in their original language. Her favorite comic is the epic manga Pirate Story, and in her first meeting with John they bonded over their shared love of it. When he returned to Earth during the crisis with Crash and reconnected with June, she caught him up on where the story is. She and John have largely similar tastes in manga, but she dislikes "that romance shit" he likes to read and instead likes to read horror manga which John in turn finds unsettling.
- June is a skilled cook, though nowhere near to the level of Thuro. Despite this, the three sarans have each said they vastly prefer her cooking to Thuro's who they've all said tends to make his meals too elaborate. She says that during her early friendship with John trying to cook for him, she learned what foods appeal to the saran pallette.