William Cunningham Deane-Tanner was born into the Anglo-Irish gentry on 26 April 1872, at Evington House, County Carlow, Ireland, one of five children of a retired British Army officer, Major Kearns Deane-Tanner of the Carlow Rifles, and his wife, Jane O'Brien. His siblings were Denis Gage Deane-Tanner, Ellen "Nell" Deane-Tanner Faudel-Phillips, Lizzie "Daisy" Deane-Tanner, and Oswald Kearns Deane-Tanner. The Home Rule MP Charles Kearns Deane Tanner was his father's youngest brother.

From 1885-1887 Taylor attended Marlborough College in England. In 1890, Taylor left Ireland for a dude ranch in Kansas. At the time, it was a short-lived trend among some of the Anglo-Irish and English gentry to send their sons to the United States to become "gentleman farmers". In Kansas, william became reacquainted with acting (his first experiences being at school) and eventually moved to New York.

While in New York, he courted Ethel May Hamilton, an Actress who had appeared in the stage musical Florodora under the name Ethel May Harrison. Her Father was a broker, and was an investor in the English antiques store on Fifth Avenue, the Antique Shoppe, that employed Taylor. The couple married in an Episcopal ceremony on 7 December 1901, at the Little Church Around the Corner, and had a daughter in 1902 or 1903. Taylor was active socially, belonging to a yacht club, and known to carry on affairs with women. The Deane-Tanners were well known in New York society and members of several clubs. He was known as a ladies' man and a heavy drinker, possibly depressed, when he abruptly vanished on 23 October 1908, at the age of 36, deserting his wife and their daughter, Ethel Daisy. After Taylor's disappearance, friends said he had suffered "mental lapses" before, and his family thought at first he had wandered off during an episode of amnesia. His wife obtained a state decree of divorce in 1912.

Little is known of the years immediately following his disappearance. He traveled through Canada, Alaska, and the northwestern United States, gold mining and working with various acting troupes. Eventually, he switched from acting to producing. By the time he arrived in San Francisco around 1912, william Deane-Tanner had changed his name to william Desmond Taylor; In San Francisco, some New York acquaintances met him, and provided him with some money to re-establish himself in Los Angeles.

In Hollywood, Taylor worked as a movie actor starting in 1913, including four appearances opposite Margaret "Gibby" Gibson. He directed his first film, The Awakening, in 1914, as an actor-director. Over the next few years, he directed more than 50 films.

Between 1914 and 1919, Taylor was engaged to Actress Neva Gerber, whom he had met during the filming of The Awakening. Gerber later recalled, "He was the soul of honour, a man of personal culture, education, and refinement. I have never known a finer or better man."

Around 1915, Taylor made contact with a sister-in-law, Ada Brennan Deane-Tanner, wife of Taylor's younger brother Denis. A former British Army lieutenant and manager of New York antiques Business (separate from Taylor's), Denis had also abandoned his wife and children, disappearing in 1912. Ada and her daughters moved to Monrovia, California, where Ada could be treated at the Pottinger Sanitorium for tuberculosis. Ada's sister, Lillian Pomeroy, was married to the sanitorium's physician in charge, Dr. John L. Pomeroy. Taylor decided to send Ada a monthly check in the amount of $50.00 to help her support her children, after her husband's abandonment. This would become public after Taylor's murder, and the press descended upon the little town of Monrovia.

Margaret Gibson was a film Actress who had worked with Taylor when he first came to Hollywood. In 1917, she was indicted, tried, and acquitted on charges equivalent to prostitution (also with allegations of opium dealing), after which she changed her professional name to Patricia Palmer. In 1923, Gibson was arrested and jailed on extortion charges, which were later dropped. Gibson was 27 years old and in Los Angeles at the time of the murder. No record of her name was ever mentioned in connection with the investigation. Soon after the murder, she got work in a number of films produced by Famous Players-Lasky, Taylor's studio at the time of his death.

By this time, Taylor's ex-wife and daughter were aware that he was working in Hollywood. In 1918, while watching the film Captain Alvarez, they saw Taylor appear on the screen. Ethel responded, "That's your Father!" In response, Ethel Daisy wrote Taylor in care of the studio. In 1921, Taylor visited his ex-wife and daughter in New York City and made Ethel Daisy his legal heir.

After returning from military Service, Taylor went on to direct some of the most popular stars of the era, including Mary Pickford, Wallace Reid, Dustin Farnum and his protégée, Mary Miles Minter, who starred in the 1919 version of Anne of Green Gables.

A spate of newspaper-driven Hollywood scandals during the early 1920s included Taylor's murder, the Roscoe Arbuckle trial, the death of Olive Thomas, the mysterious death of Thomas H. Ince, and the drug-related deaths of Wallace Reid, Barbara La Marr, and Jeanne Eagels, all of which prompted Hollywood studios to begin writing contracts with "morality clauses" or "moral turpitude clauses", allowing the dismissal of contractees who breached them.

In Taylor's pockets, investigators found a wallet holding $78 in cash, a silver cigarette case, a Waltham pocket watch, a pen knife, and a locket bearing a photograph of Actress Mabel Normand. A two-carat Diamond ring was on his finger. With the evidence of the money and valuables on Taylor's body, robbery seemingly was not the motive for the killing; however, a large but undetermined sum of cash that Taylor had shown to his accountant the day before was missing and apparently never accounted for. After some investigation, the time of Taylor's death was set at 7:50 pm on the evening of 1 February 1922.

Ultimately, Normand continued to make films throughout the 1920s. She died of tuberculosis on 23 February 1930. According to her friend and confidante Julia Brew, Normand asked her a few days before she died: "Julia, do you think they'll ever find out who killed Bill Taylor?"

In 1931, Peavey died in a San Francisco asylum where he had been hospitalized for syphilis-related dementia.

Perhaps the most compelling bit of circumstantial evidence was that Shelby allegedly owned a rare .38-caliber pistol and some unusual bullets which were very similar to the kind which had killed Taylor. After this information became public, she reportedly threw the pistol into a Louisiana bayou. Shelby knew the Los Angeles district attorney socially and spent years outside the United States, in an effort to avoid both official inquiries by his successor and press coverage related to the murder. In 1938, her other daughter, Actress Margaret Shelby (who was by then suffering from both clinical depression and alcoholism), openly accused her mother of the murder. Shelby was widely suspected of the crime and was a favorite suspect of many Writers. For Example, Adela Rogers St. Johns speculated that Shelby was torn by feelings of maternal protection for her daughter and her own attraction to Taylor. Although (like Edward Sands) Shelby feared being tried for the murder, at least two Los Angeles County district attorneys publicly declined to prosecute her. Almost 20 years after the murder, Los Angeles district attorney Buron Fitts concluded evidence was insufficient for an indictment of Shelby and recommended that the remaining evidence and case files be retained on a permanent basis (all of these materials subsequently disappeared). Shelby died in 1957. Fitts, in ill health, committed suicide in 1973.

The bungalows were demolished in the 1960s. The actual murder location is a parking lot near Alvarado and Maryland Streets. The parking lot has served Pic 'n Save, Alpha Beta Supermarket, and, as of 2017, Ross and Dollar Tree.

According to Robert Giroux, "The studios seemed to be fearful that if certain aspects of the case were exposed, it would exacerbate their problems." King Vidor said of the case in 1968: "Last year I interviewed a Los Angeles police detective, now retired, who had been assigned to the case immediately after the murder. He told me, 'We were doing all right and then, before a week was out, we got the word to lay off.'"

However, facsimiles of Minter's passionate letters to Taylor were printed in newspapers, forever shattering her screen image as a modest and wholesome young girl. Minter was vilified in the press. She made four more films for Paramount, and when the studio failed to renew her contract, she received offers from many other producers. Never comfortable as an Actress, Minter declined them all. In 1957, she married Brandon O. Hildebrandt, a Danish-American businessman. She died in Santa Monica, California, on 4 August 1984.

Through a combination of poor crime-scene management and apparent corruption, much physical evidence was immediately lost and the rest vanished over the years, although copies of a few documents from the police files were made public in 2007. Various theories were put forward after the murder and in the years since, and many books were published, claiming to have identified the murderer, but no hard evidence was ever uncovered to link the crime to a particular individual.

Charlotte Shelby was Minter’s mother. Like many stage mothers before and since, she has been described as manipulative and consumed by wanton greed over her daughter's career. Minter and her mother were bitterly divided by financial disputes and lawsuits for a time, but they later reconciled. Shelby's initial statements to police about the murder are still characterized as evasive and "obviously filled with lies" about both her daughter's relationship with Taylor and "other matters".