Born in Seattle, Washington, in 1957, to Hester Crane, a psychiatrist, and Martin Crane, a police detective, the exact date of Niles' birth is never revealed. He´s two years younger than Frasier. There are well over a dozen character and story-telling errors about Marty Crane contained in the Frasier series episodes, listed here .
Like Frasier, Niles was named for one of his mother's lab rats (Are you Being Served). Also like Frasier, Niles was an unusually sensitive child when growing up, and a frequent target for bullies. As a result, he was quite close to his older brother, and at the same time fiercely competitive with him. Like Frasier, Niles also preferred fine arts, music, and intellectual pursuits to boyhood activities like sports.
Niles' success in school led to his attendance at Yale University in New Haven, Connecticut (like his counterpart David Hyde Pierce) as an undergraduate, and the Yale School of Medicine for both his M.D. and Ph.D. in psychiatry. He subsequently attended the University of Cambridge in Cambridge, England, where he was a postdoctoral fellow while completing his professional training. This further highlights the close competitive relationship with his brother, Frasier, who attended Harvard University in Cambridge, Massachusetts as an undergraduate, then Harvard Medical School for both his M.D. and Ph.D. in psychiatry, subsequently followed by his own postdoctoral fellowship at the University of Oxford in Oxford, England.
Niles describes his profession as "the saving grace of my life" (in episode "IQ") and is greatly respected professionally. He runs his own Jungian practice (Frasier is a Freudian) and has had his research published in several psychiatric journals. Niles often compares his own career to that of his brother's, and early in the series makes frequent wisecracks about the "pop psychiatry" that Frasier practices through his radio show. Over the course of the show his remarks reduce down to occasional jabs for the purpose of humor. It is revealed that Niles lashed out at his brother due to jealousy, as he felt that he did not receive the praise and recognition due for his hard work, whereas Frasier's face is seen on "the side of buses." This sibling conflict is one of the main ones explored in the series.
Personality
Niles is fastidious, snobby and fussy, and has gourmet tastes. He is an admirer of the fine arts including opera, theatre and classical music, drinks fine wine and enjoys French food which he himself cooks, and frequently obsesses about knowing the right people and climbing the social ladder.
Niles is also very intelligent. In the episode IQ, it is revealed that his IQ is 156, well above the Mensa range (which is typically around the low 130s).
Physically weak and very uncoordinated, Niles has a long list of phobias and medical conditions, many of which are clearly psychosomatic. Most prominently, he is quite mysophobic, given to wiping his hands after human contact and wiping down chairs in public places before sitting on them. He has nose bleeds when he tells a direct lie, and he faints at the sight of blood. When extremely stressed, he is prone to panic attacks and fits of hyperventilation which have, on more than one occasion, seen him lose consciousness. He also suffers from a long list of allergies, some exceedingly rare. He is seemingly hopeless at sports, barely able to catch objects even after simple throws. However, in some episodes he is shown to be fair at basketball. On one occasion, while attending a basketball game, he is fortuitously invited on court during the game's intermission to try his skill (or luck) at scoring from half court, and much to the astonishment of his brother and father (and himself), Niles makes the impossible throw. The brothers are often seen coming or going to squash matches, though Martin once commented in disbelief, "You have to wonder what happens on that squash court." Accompanying Martin on the shooting range one day, Niles discovered that he is an excellent marksman. He is a fair fencer, and has had some lessons in kickboxing. On other occasions he has expressed interest in lifting weights and taking karate lessons, but these ventures are typically laughed at by his father and brother and often amount to nothing. He is also a master speller, having come close to winning the national spelling competition as a youth.
He drives a Mercedes-Benz with the licence plate 5HR1NK. It is unknown which Mercedes he drives in the latter half of the series but in a second season episode, he states that he drives a Mercedes-Benz E320.
Roles in the Series
Niles is Frasier's constant companion and rival. He meets with his brother every day at Cafe Nervosa, where they discuss their lives and various other topics. Niles and Frasier often collaborate on projects, which frequently and comedically lead to complete disaster. Some examples are the book (ironically about sibling rivalry) that they attempted to write in the episode Author, Author and the restaurant they purchase, and attempt to transform into an exclusive five-star eatery in the episode The Innkeepers.
His romantic life is another area explored throughout the series, and it is tragically plagued with grief and misfortune.
Niles' first wife is Maris Crane, the selfish, haughty, highly-strung, anorexic, and unstable daughter of a wealthy Seattle family, who is never seen on the show, despite being referred to frequently. Maris demonstrates her extremely paranoid and controlling nature throughout the series. Her lack of respect and affection for Niles leads to separation, and eventually a rancorous divorce after fifteen years of marriage. After taking away nearly everything he owned, she finally agrees on a settlement when Niles' attorney threatens to expose the fact that her family's wealth is not in timber lands but in urinal cakes.
Niles then marries Mel Karnofsky, Maris' plastic surgeon, whom he starts dating following his divorce. The two elope, but the marriage falls apart after only two days when Niles confesses his love for Daphne Moon Crane, his father's physical therapist, to whom he had been secretly attracted throughout the series' first seven seasons. His confession occurs the night before her wedding to Niles' divorce lawyer Donny Douglas. The relationship spawns a huge ordeal, prompting Donny to respond by suing both Daphne and Frasier, while Mel forces Niles to participate in a prolonged charade of a happy marriage for the sake of appearances, until he finally loses his temper and shouts out the truth during an important dinner party.
Niles' most significant relationship on the show is with Daphne Moon Crane, perhaps an unlikely attraction given the significant differences in their tastes, temperament and social standing (he once referred to her as a "working-class Venus"). For numerous reasons during the first six seasons of the show, Niles is unable to confess his feelings for Daphne, who remains unaware of his love for her (despite her professed psychic abilities).
Niles' feelings for Daphne are the basis for many gags on the show, including the numerous ways he demonstrates how besotted he is with her (such as being entranced by the smell of her hair or staring at her rear end when she bends over), but develops over the course of the series into an important plot line. Pierce engaged in innumerable bits of nearly unnoticeable stage business, displaying Niles' almost trance-like attraction to Daphne even when audience focus of attention is not on the pair. Niles is frequently jealous of Daphne's boyfriends (and even his own nephew, Frederick, who nurses a crush on Daphne as a pre-adolescent). Niles does tell Frasier repeatedly that he is over Daphne when she accepts Donny Douglas' proposal of marriage, and proceeds to marry Mel in a kind of rebound, but admits that he still loves Daphne when on the eve of her wedding, Frasier tells him that Daphne knows of Niles' feelings and reciprocates them.
When the two do attempt a relationship, they must reconcile their many lifestyle differences, and Daphne is so worried she will not live up to Niles' idealistic vision of her that she begins over indulging on chocolate. She gains over sixty pounds, but Niles doesn't even notice. Daphne finally reaches her breaking point when she falls to the floor and is too heavy to get up without the help of Frasier, Niles and Martin (who quips, "Hey Daph I just thought of something funny, it took three Cranes to lift you"). She is absent from the next few episodes, losing weight at a spa. (This storyline was developed to conceal the real reason actress Jane Leeves was putting on weight -- she was pregnant.) Forunately, in the end the couple finds compatibility, and many of Niles' nervous eccentricities diminish as he finally manages to maintain a stable relationship.
Ultimately Niles and Daphne marry in Reno, Nevada, and the series ends with the birth of their son, David, who is born at a veterinary clinic. David is named after Frasier co-creator David Angell who was killed, along with his wife Lynn, in the crash of American Airlines Flight 11 in the September 11, 2001 attacks.
Niles' last line is "I'll miss the coffees."