Bundy was born Theodore Robert Cowell on November 24, 1946, to Eleanor Louise Cowell (1924–2012) (known for most of her life as Louise) at the Elizabeth Lund Home for Unwed Mothers in Burlington, Vermont. His father's identity was never determined with any degree of certainty. His birth certificate assigned paternity to a salesman and Air Force veteran named Lloyd Marshall, but Louise later claimed that she had been seduced by "a sailor" whose name may have been Jack Worthington. Years later, investigators would find no record of anyone by that name in Navy or Merchant Marine archives. Some family members expressed suspicions that Bundy might have been fathered by Louise's own violent, abusive father, Samuel Cowell, but no material evidence has ever been cited to support or refute this.

In 1950, Louise abruptly changed her surname from Cowell to Nelson, and at the urging of multiple family members, she left Philadelphia with her son to live with cousins Alan and Jane Scott in Tacoma, Washington. In 1951 Louise met Johnny Culpepper Bundy, a hospital cook, at an adult singles night at Tacoma's First Methodist Church. They married later that year and Johnny Bundy formally adopted Ted. Johnny and Louise conceived four children of their own, and although Johnny tried to include his adoptive son in camping trips and other family activities, Ted remained distant. He later complained to his girlfriend that Johnny wasn't his real father, "wasn't very bright", and "didn't make much money."

After graduating from high school in 1965, Bundy spent a year at the University of Puget Sound (UPS) before he transferred to the University of Washington (UW) in 1966 to study Chinese. In 1967, he became romantically involved with a UW classmate who is identified by several pseudonyms in Bundy biographies, most commonly Stephanie Brooks. In early 1968 he dropped out of college and worked at a series of minimum-wage jobs. He also volunteered at the Seattle office of Nelson Rockefeller's presidential campaign and in August attended the 1968 Republican National Convention in Miami as a Rockefeller delegate. Shortly thereafter Brooks ended their relationship and returned to her family home in California, frustrated by what she described as Bundy's immaturity and lack of ambition. Psychiatrist Dorothy Lewis would later pinpoint this crisis as "probably the pivotal time in his development". Devastated by Brooks's rejection, Bundy traveled to Colorado and then farther east, visiting relatives in Arkansas and Philadelphia and enrolling for one semester at Temple University. It was at this time in early 1969, Rule believes, that Bundy visited the office of birth records in Burlington and confirmed his true parentage.

Bundy's 1968 Volkswagen Beetle was displayed in the lobby of the National Museum of Crime and Punishment in Washington DC until its closure in 2015. It is presently on exhibit at the Alcatraz East Crime Museum in Pigeon Forge, Tennessee.

There is no consensus on when or where Bundy began killing women. He told different stories to different people and refused to divulge the specifics of his earliest crimes, even as he confessed in graphic detail to dozens of later murders in the days preceding his execution. He told Nelson that he attempted his first kidnapping in 1969 in Ocean City, New Jersey, but did not kill anyone until sometime in 1971 in Seattle. He told Psychologist Art Norman that he killed two women in Atlantic City in 1969 while visiting family in Philadelphia. He hinted but refused to elaborate to homicide detective Robert D. Keppel that he committed a murder in Seattle in 1972 and another murder in 1973 that involved a hitchhiker near Tumwater, Washington. Rule and Keppel both believed that he might have started killing as a teenager. Circumstantial evidence suggested that he abducted and killed 8-year-old Ann Marie Burr of Tacoma when he was 14 years old in 1961; this was an allegation that he repeatedly denied. His earliest documented homicides were committed in 1974 when he was 27 years old. By his own admission, he had mastered the necessary skills—in the era before DNA profiling—to leave minimal incriminating forensic evidence at the crime scene.

After graduating from UW in 1972 Bundy joined Governor Daniel J. Evans' re-election campaign. Posing as a college student, he shadowed Evans' opponent, former governor Albert Rosellini, and recorded his stump speeches for analysis by Evans' team. After Evans was re-elected, Bundy was hired as an assistant to Ross Davis, Chairman of the Washington State Republican Party. Davis thought well of Bundy and described him as "smart, aggressive ... and a believer in the system". In early 1973, Bundy was accepted into the law schools of UPS and the University of Utah despite mediocre Law School Admission Test scores. He got in on the strength of letters of recommendation from Evans, Davis, and several UW psychology professors.

During a trip to California on Republican Party Business in the summer of 1973, Bundy rekindled his relationship with Brooks, who marveled at his transformation into a serious, dedicated professional who was seemingly on the cusp of a distinguished legal and political career. He continued to date Kloepfer as well, and neither woman was aware of the other's existence. In the fall of 1973, Bundy matriculated at UPS Law School and continued courting Brooks, who flew to Seattle several times to stay with him. They discussed marriage; at one point he introduced her to Davis as his fiancée. In January 1974, however, he abruptly broke off all contact; her phone calls and letters went unreturned. Finally reaching him by phone a month later, Brooks demanded to know why Bundy had unilaterally ended their relationship without explanation. In a flat, calm voice, he replied, "Stephanie, I have no idea what you mean" and hung up. She never heard from him again. He later explained, "I just wanted to prove to myself that I could have married her"; but Brooks concluded in retrospect that he had deliberately planned the entire courtship and rejection in advance as vengeance for the breakup she initiated in 1968.

Bundy also confided in Special Agent william Hagmaier of the FBI Behavioral Analysis Unit. Hagmaier was struck by the "deep, almost mystical satisfaction" that Bundy took in murder. "He said that after a while, murder is not just a crime of lust or violence", Hagmaier related. "It becomes possession. They are part of you ... [the victim] becomes a part of you, and you [two] are forever one ... and the grounds where you kill them or leave them become sacred to you, and you will always be drawn back to them." Bundy told Hagmaier that he considered himself to be an "amateur", an "impulsive" killer in his early years, before moving into what he termed his "prime" or "predator" phase at about the time of Lynda Healy's murder in 1974. This implied that he began killing well before 1974—though he never explicitly admitted doing so.

On August 16, 1975, Bundy was arrested by a Utah Highway Patrol officer in Granger (another Salt Lake City suburb). The officer had observed Bundy cruising a residential area in the pre-dawn hours; Bundy fled the area at high speed after seeing the patrol car. The officer searched the car after he noticed that the Volkswagen's front Passenger seat had been removed and placed on the rear seats. He found a ski mask, a second mask fashioned from pantyhose, a crowbar, handcuffs, trash bags, a coil of rope, an ice pick, and other items initially assumed to be burglary tools. Bundy explained that the ski mask was for skiing, he had found the handcuffs in a dumpster, and the rest were Common household items. However, Detective Jerry Thompson remembered a similar suspect and car description from the November 1974 DaRonch kidnapping, which matched Bundy's name from Kloepfer's December 1974 phone call. In a search of Bundy's apartment, police found a guide to Colorado ski resorts with a checkmark by the Wildwood Inn and a brochure that advertised the Viewmont High School play in Bountiful, where Debra Kent had disappeared. The police did not have sufficient evidence to detain Bundy, and he was released on his own recognizance. Bundy later said that searchers missed a collection of Polaroid photographs of his victims; he destroyed the photographs after he was released.

On February 23, 1976, Bundy stood trial for the DaRonch kidnapping. On the advice of his attorney, John O'Connell, Bundy waived his right to a jury due to the negative publicity surrounding the case. On March 1, after a four-day bench trial and a weekend of deliberation, Judge Stewart Hanson Jr. found him guilty of kidnapping and assault. On June 30, he was sentenced to serve a minimum of one to a maximum of 15 years in the Utah State Prison. In October, he was found hiding in bushes in the prison yard carrying an "escape kit"—road maps, airline schedules, and a social security card—and spent several weeks in solitary confinement. Later that month, Colorado authorities charged him with Caryn Campbell's murder. After a period of resistance, he waived extradition proceedings and was transferred to Aspen in January 1977.

While Nelson was apparently convinced that Bundy's concern was genuine, most biographers, researchers, and other observers have concluded that his sudden condemnation of pornography was one last manipulative attempt to shift blame by catering to Dobson's agenda as a longtime pornography critic. He told Dobson that "true crime" detective magazines had "corrupted" him and "fueled [his] fantasies ... to the point of becoming a serial killer"; yet in a 1977 letter to Ann Rule, he wrote, "Who in the world reads these publications? ... I have never purchased such a magazine, and [on only] two or three occasions have I ever picked one up." He told Michaud and Aynsworth in 1980, and Hagmaier the night before he spoke to Dobson, that pornography played a negligible role in his development as a serial killer. "The Problem wasn't pornography", wrote Dekle. "The Problem was Bundy." "I wish I could believe that his motives were altruistic," wrote Rule. "But all I can see in that Dobson tape is another Ted Bundy manipulation of our minds. The effect of the tape is to place, once again, the onus of his crimes, not on himself, but on us."

In the early hours of January 15, 1978—one week after his arrival in Tallahassee—Bundy entered FSU's Chi Omega sorority house through a rear door with a faulty locking mechanism. Beginning at about 2:45 a.m. he bludgeoned Margaret Bowman, 21, with a piece of oak firewood as she slept, then garroted her with a nylon stocking. He then entered the bedroom of 20-year-old Lisa Levy and beat her unconscious, strangled her, tore one of her nipples, bit deeply into her left buttock, and sexually assaulted her with a hair mist bottle. In an adjoining bedroom he attacked Kathy Kleiner, breaking her jaw and deeply lacerating her shoulder; and Karen Chandler, who suffered a concussion, broken jaw, loss of teeth, and a crushed finger. Tallahassee detectives later determined that the four attacks took place in a total of less than 15 minutes, within earshot of more than 30 witnesses who heard nothing. After leaving the sorority house, Bundy broke into a basement apartment eight blocks away and attacked FSU student Cheryl Thomas, dislocating her shoulder and fracturing her jaw and skull in five places. She was left with permanent deafness, and equilibrium damage that ended her dance career. On Thomas's bed, police found a semen stain and a pantyhose "mask" containing two hairs "similar to Bundy's in class and characteristic".

At trial, crucial testimony came from Chi Omega sorority members Connie Hastings, who placed Bundy in the vicinity of the Chi Omega House that evening, and Nita Neary, who saw him leaving the sorority house clutching the oak murder weapon. Incriminating physical evidence included impressions of the bite wounds Bundy had inflicted on Lisa Levy's left buttock, which forensic odontologists Richard Souviron and Lowell Levine matched to castings of Bundy's teeth. The jury deliberated for less than seven hours before convicting him on July 24, 1979, of the Bowman and Levy murders, three counts of attempted first degree murder (for the assaults on Kleiner, Chandler and Thomas) and two counts of burglary. Trial judge Edward Cowart imposed death sentences for the murder convictions.

Bundy confessed to 30 homicides, but the true total remains unknown. Published estimates have run as high as 100 or more, and Bundy occasionally made cryptic comments to encourage that speculation. He told Hugh Aynesworth in 1980 that for every murder "publicized", there "could be one that was not." When FBI agents proposed a total tally of 36, Bundy responded, "Add one digit to that, and you'll have it." Years later he told attorney Polly Nelson that the Common estimate of 35 was accurate, but Robert Keppel wrote that "[Ted] and I both knew [the total] was much higher." "I don't think even he knew ... how many he killed, or why he killed them", said Rev. Fred Lawrence, the Methodist clergyman who administered Bundy's last rites. "That was my impression, my strong impression."

While experts found Bundy's precise diagnosis elusive, the majority of evidence pointed away from bipolar disorder or other psychoses, and toward antisocial personality disorder (ASPD). Bundy displayed many personality traits typically found in ASPD patients (who are often identified as "sociopaths" or "psychopaths"), such as outward charm and charisma with little true personality or genuine insight beneath the facade; the ability to distinguish right from wrong, but with minimal effect on behavior; and an absence of guilt or remorse. "Guilt doesn't solve anything, really", Bundy said, in 1981. "It hurts you ... I guess I am in the enviable position of not having to deal with guilt." There was also evidence of narcissism, poor judgment, and manipulative behavior. "Sociopaths", prosecutor George Dekle wrote, "are egotistical manipulators who think they can con anybody." "Sometimes he manipulates even me", admitted one Psychiatrist. In the end, Lewis agreed with the majority: "I always tell my graduate students that if they can find me a real, true psychopath, I'll buy them dinner", she told Nelson. "I never thought they existed ... but I think Ted may have been one, a true psychopath, without any remorse or empathy at all." Narcissistic personality disorder (NPD) has been proposed as an alternative diagnosis in at least one subsequent retrospective analysis.

In October 1982, Boone gave birth to a daughter and named Bundy as the father. While conjugal visits were not allowed at Raiford Prison, inmates were known to pool their money in order to bribe guards to allow them intimate time alone with their female visitors.

Sometime during this period, Bundy was attacked by a group of his fellow death row inmates. Though he denied having been assaulted, a number of inmates confessed to the crime, characterized by one source as a "gang rape". Shortly thereafter, he was charged with a disciplinary infraction for unauthorized correspondence with another high-profile Criminal, John Hinckley, Jr. In October 1984, Bundy contacted Robert Keppel and offered to share his self-proclaimed expertise in serial killer psychology in the ongoing hunt for his successor in Washington, the Green River Killer. Keppel and Green River Task Force detective Dave Reichert interviewed Bundy, but Gary Leon Ridgway remained at large for a further 17 years. Keppel published a detailed documentation of the Green River interviews, and later collaborated with Michaud on another examination of the interview material.

Less than 15 hours before the scheduled July 2 execution, the Eleventh Circuit Court of Appeals stayed it indefinitely and remanded the Chi Omega case for review on multiple technicalities—including Bundy's mental competency to stand trial, and an erroneous instruction by the trial judge during the penalty phase requiring the jury to break a 6–6 tie between life imprisonment and the death penalty—that, ultimately, was never resolved. A new date (November 18, 1986) was then set to carry out the Leach sentence; the Eleventh Circuit Court issued a stay on November 17. In mid-1988, the Eleventh Circuit ruled against Bundy, and in December the Supreme Court denied a motion to review the ruling. Within hours of that final denial, a firm execution date of January 24, 1989, was announced. Bundy's journey through the appeals courts had been unusually rapid for a capital murder case: "Contrary to popular belief, the courts moved Bundy as fast as they could ... Even the prosecutors acknowledged that Bundy's lawyers never employed delaying tactics. Though people everywhere seethed at the apparent delay in executing the archdemon, Ted Bundy was actually on the fast track."

Bundy remains a suspect in several unsolved homicides, and is likely responsible for others that may never be identified; in 1987 he confided to Keppel that there were "some murders" that he would "never talk about", because they were committed "too close to home", "too close to family", or involved "victims who were very young".

Hagmaier was present during Bundy's final interviews with investigators. On the eve of his execution, he talked of suicide. "He did not want to give the state the satisfaction of watching him die", Hagmaier said. Ted Bundy died in the Raiford electric chair at 7:16 a.m. EST on January 24, 1989; he was 42 years old. Hundreds of revelers—including 20 off-duty police officers, by one account—sang, danced and set off fireworks in a pasture across the street from the prison as the execution was carried out, then cheered loudly as the white hearse containing Bundy's corpse departed the prison. His remains were cremated in Gainesville, and the ashes scattered at an undisclosed location in the Cascade Range of Washington State, in accordance with his will.

Denise Lynn Oliverson, 25, disappeared near the Utah–Colorado border in Grand Junction on April 6 while riding her bicycle to her parents' house; her bike and sandals were found under a viaduct near a railroad bridge. On May 6, Bundy lured 12-year-old Lynette Dawn Culver from Alameda Junior High School in Pocatello, Idaho, 160 miles (260 km) north of Salt Lake City. He drowned and then sexually assaulted her in his hotel room, before disposing of her body in a river north of Pocatello (possibly the Snake).

Minutes before his execution, Hagmaier queried Bundy about unsolved homicides in New Jersey, Illinois, Vermont (the Curran case), Texas, and Miami, Florida. Bundy provided directions—later proven inaccurate—to Susan Curtis's burial site in Utah, but denied involvement in any of the open cases.