On the morning of June 25, 2009, Jackson reportedly collapsed at a home he was renting in west Los Angeles. Paramedics responded to a 911 call at 12:21 pm local time. He reportedly was not breathing at the time that paramedics arrived, and CPR was quickly performed. He fell into a coma and died shortly after being rushed to the UCLA hospital. The cause of death is suspected to be cardiac arrest. Jackson was pronounced dead at 2:26 p.m Pacific Time. At 4:36 pm local time, the Los Angeles coroner confirmed Jackson's death. Although there is no evidence of criminality, Los Angeles Police Department detectives have opened an investigation into his death.

Jackson has been singing since a child, and over time his voice and vocal style have notably changed, either through puberty or a personal preference to align his vocal interpretation to the themes and genres he chooses to express. Between 1971 and 1975, Jackson's voice "descended ever so slightly from boy soprano to his current androgynous high tenor". In the mid-1970s, the singer adopted a "vocal hiccup" as seen in "Shake Your Body (Down to the Ground)". The purpose of the hiccup—somewhat like a gulping for air or gasping—is to help promote a certain emotion; be it excitement, sadness or fear. With the arrival of Off the Wall in the late 1970s, Jackson's abilities as a vocalist were well regarded; Allmusic described him as a "blindingly gifted vocalist". At the time, Rolling Stone compared his vocals to the "breathless, dreamy stutter" of Stevie Wonder. Their analysis was also that "Jackson's feathery-timbered tenor is extraordinary beautiful. It slides smoothly into a startling falsetto that's used very daringly". 1982 saw the release of Thriller, and Rolling Stone were of the opinion that Jackson was then singing in a "fully adult voice" that was "tinged by sadness".
The release of "Bad" in 1987 displayed gritty lead vocals on the verse and lighter tones employed on the chorus. A distinctive deliberate mispronunciation used frequently by Jackson, occasionally spelt "cha'mone" or "shamone", is also a staple in impressions and caricatures of him. The turn of the 1990s saw the release of the paradoxical, introspective album Dangerous, here Jackson used his vocals to intensify the split themes and genres described earlier. The New York Times noted that on some tracks, "he gulps for breath, his voice quivers with anxiety or drops to a desperate whisper, hissing through clenched teeth" and he had a "wretched tone". When singing of brotherhood or self-esteem the musician would return to "smooth" vocals. "In the Closet" contained heavy breathing and a loop of five scat-sung syllables, whereas in the albums title track, Jackson performs a spoken rap. When commenting on Invincible, Rolling Stone were of the opinion that—at the age of 43—Jackson still performed, "exquisitely voiced rhythm tracks and vibrating vocal harmonies". Nelson George summed by Jackson's vocals as, "The grace, the aggression, the growling, the natural boyishness, the falsetto, the smoothness—that combination of elements mark him as a major vocalist".

Steve Huey of Allmusic observes the fact that Jackson transformed the music video into an art form and a promotional tool through complex story lines, dance routines, special effects and famous cameo appearances; simultaneously breaking down racial barriers. According to director Vincent Paterson, who collaborated with the singer on several music videos, Jackson conceptualized many of the darker, bleak themes in his filmography.
Before the success of the Thriller album, Jackson struggled to receive coverage on MTV because he was African American. Pressure from CBS Records persuaded MTV to start showing "Billie Jean" and later "Beat It", leading to a lengthy partnership with Jackson that helped other black music artists gain recognition. The popularity of his video on MTV helped to put the relatively young channel "on the map"; MTV's focus shifted in favor of pop and R&B. Short films like Thriller largely remained unique to Jackson, while the group dance sequence in "Beat It" has frequently been imitated. The choreography in Thriller has become a part of global pop culture, replicated everywhere from Bollywood to prisons in the Philippines. The Thriller short film marked an increase in scale for music videos, and has been named the most successful music video ever by the Guinness World Records.
In the 18-minute music video for "Bad"—directed by Martin Scorsese—Jackson began using sexual imagery and choreography not previously seen in his work. He occasionally grabbed or touched his chest, torso and crotch. While he has described this as "choreography," it garnered a mixed reception from both fans and critics; Time magazine described it as "infamous". The video also featured Wesley Snipes; Jackson's videos would often feature famous cameos roles in the future. For "Smooth Criminal", Jackson experimented with an innovative "anti-gravity lean" in his performances, for which he was granted US Patent No. 5,255,452. Although the music video for "Leave Me Alone" was not officially released in the US, in 1989, it was nominated for four Billboard Music Video Awards, winning three; the same year it won a Golden Lion Award for the quality of the special effects used in its production. In 1990, "Leave Me Alone" won a Grammy for Best Music Video, Short Form.
The MTV Video Vanguard Artist of the Decade Award was given to Jackson to celebrate his accomplishments in the art form in the 1980s; the following year the award was renamed in his honor. "Black or White" was accompanied by a controversial music video, which, on November 14, 1991, simultaneously premiered in 27 countries with an estimated audience of 500 million people, the largest viewing ever for a music video. It featured scenes construed as having a sexual nature as well as depictions of violence. The offending scenes in the final half of the 14-minute version were edited out to prevent the video from being banned, and Jackson apologized. Along with Jackson, it featured Macaulay Culkin, Peggy Lipton and George Wendt. It helped usher in morphing as an important technology in music videos.
"Remember the Time" was an elaborate production, and became one of his longest videos at over nine minutes. Set in ancient Egypt, it featured groundbreaking visual effects and appearances by Eddie Murphy, Iman and Magic Johnson, along with a distinct complex dance routine. The video for "In the Closet" was Jackson's most sexually provocative piece to date. It featured supermodel Naomi Campbell in a courtship dance with Jackson. The video was banned in South Africa because of its imagery.
The music video for "Scream", directed by Mark Romanek and production designer Tom Foden, is one of Jackson's most critically acclaimed. In 1995, it gained 11 MTV Video Music Award Nominations—more than any other music video—and won "Best Dance Video", "Best Choreography", and "Best Art Direction". The song and its accompanying video are a response to the backlash Jackson received from the media after