Lawrence Parker was born in the New York City borough of Brooklyn in 1965 to an American mother. His biological father, who was not involved in his upbringing, was from the Caribbean island of Barbados.^[3] He had a troubled childhood, suffering severe beatings^[4]from his American stepfather John Parker^[5] when the family lived in Harlem, New York.^[6] When his mother left the marriage both he and his younger brother Kenny moved with her to the Bronx,^[7]before again moving a year later to Brooklyn.^[8]Home life continued to be difficult, including further physical abuse at the hands of his mother's new Jamaican partner,^[9] and he ran away from home several times.^[10]

At age 16 he left home permanently, and spent a time living homeless in New York,^[11] before eventually signing himself into a group home^[12] in the Bronx.

Growing up, Parker had developed a deep love of the emerging hip hop culture in New York, and by that time he was honing his craft as an MC, as well as being an active graffiti writer.^[12] In 1984, he left the group home and moved into a homeless shelter^[12] in the South Bronx where he was dubbed "Krishna" by the residents due to his curiosity about the Hare Krishna spirituality of some of the anti-poverty workers.^[13] During his stay at the community shelter he encountered youth counsellor Scott Sterling a.k.a. DJ Scott La Rock and there began a DJ-MC relationship. He also engaged in the street art activity graffitiunder the alias KRS-One (Knowledge Reigns Supreme Over Nearly Everyone^{[citation needed]}). Together he and Sterling created Boogie Down Productions, releasing their debut album, Criminal Minded, in 1987.^[14]

KRS-One also practices activism in his career and is a leading figure and founder of several hip hop groups that worked to promote peace and education, such as the Stop the Violence Movement and Human Education Against Lies (H.E.A.L.). He also founded the Temple of Hip Hop, a group dedicated to preserving and expanding hip hop culture and spirituality.^[15]Through this, KRS-One intends to decriminalize Hiphop and "raise hip-hop's identity and self-esteem".^[16] In an Interview with Aki X in the January 2003 issue of Thrasher Magazine, KRS-One observes: "Hip-hop has manifested Martin Luther Kings "I Have A Dream" speech where he envisioned that the sons and daughters of former slave owners and sons and daughters of former slaves would join hands in brotherhood towards justice and freedom. Hip-hop express that through Eminem and Dr Dre, through Russell simmons and the Beastie Boys, through MC, search. Run DMC and Aerosmith. This is what it is to be hip-hoppa."^[17]

In KRS-One's song, "Outta Here", he reflects on the early days of New York hip-hop, influenced by acts like Run-DMC and Whodini, who he heard on the Awesome Two's radio show on WHBI. KRS-One explains how the release of BDP's "Criminal Minded", and Eric B and Rakim's "Paid in Full" had the unintended effect of turning both groups into Hip Hop pioneers. He also claims that his album "By All Means Necessary" and Public Enemy's "It Takes A Nation of Millions to Hold Us Back" were a main influence that set off consciousness in rap.^[12]

KRS-One began his recording career as one third of the hip hop group Boogie Down Productions, or BDP, alongside DJ Scott La Rock and Derrick "D-Nice" Jones. Additionally, KRS-One had taken offense to "The Bridge", a song by Marley Marl's protege, MC Shan (KRS-One later reconciled with Marley Marl, producing an album with him in 2007 titled Hip Hop Lives). The song could be interpreted as a claim that Queensbridge was the monument of hip-hop, though MC Shan has repeatedly denied this claim. Still, KRS-One "dissed" the song with the BDP record "South Bronx". A second round of volleys ensued with Shan's "Kill That Noise" and BDP's "The Bridge Is Over". KRS-One, demonstrating his nickname "The Blastmaster", gave a live performance against MC Shan, and many conceded he had won the battle. Many^[who?] believe this live performance to be the first MC battle where rappers attack each other, instead of a battle between who can get the crowd more hyped.^[18]

Parker and Sterling decided to form a rap group together, initially calling themselves "Scott La Rock and the Celebrity Three". That was short-lived, however, as the two peripheral members quit, leaving Parker (now calling himself KRS-One) and Sterling. They then decided to call themselves "Boogie Down Productions". "Success is the Word", a 12-inch single produced by David Kenneth Eng and Kenny Beck, was released on indie Fresh/Sleeping Bag Records (under the group name "12:41") but did not enjoy commercial success.

Boogie Down Productions released their debut album Criminal Minded in 1987. KRS-One was the first Emcee to be holding a 9mm on the album cover,^[17] and Scott La Rock was killed in a shooting later that year after attempting to mediate a dispute between teenager and BDP member D-Nice and local hoodlums.

During this time KRS-One also gained acclaim as one of the first MCs to incorporate Jamaican style into hip-hop, using the Zung gu zung melody, originally made famous by Yellowman in Jamaican dance halls earlier in the decade.^[19] This is particularly evident in the song titled "Remix for P is Free". Dancehall influence is also very prominent in the BDP hit "The Bridge is Over", which uses the same melody as Super Cat's 1986 dancehall hit "Boops",^[20] and lyrical inflections in a Jamaican style. KRS-One is credited as one of the more influential figures to bridge the gap between Jamaican music and American hip-hop.

Following the fatal shooting of Scott La Rock in 1987, KRS was determined to continue Boogie Down Productions through the tragedy, releasing the album By All Means Necessary in 1988. He was joined by beatboxer D-Nice, rapper Ramona "Ms. Melodie" Parker (whose marriage to Kris would last from 1988 to 1992^[21]), and Kris's younger brother DJ Kenny Parker, among others. However, Boogie Down Productions would remain KRS' show, and the group's content would become increasingly political through the subsequent releases Ghetto Music: The Blueprint of Hip Hop, Edutainment, Live Hardcore Worldwide and Sex and Violence.

KRS-One was the primary initiator behind the H.E.A.L. compilation and the Stop the Violence Movement; for the latter he would attract many prominent emcees to appear on the 12-inch single "Self Destruction". As KRS adopted this "humanist", less defensive approach, he turned away from his "Blastmaster" persona and towards that of "The Teacha", although he has constantly used "Blastmaster" throughout his career.

After five largely solo albums under the name "Boogie Down Productions", KRS-One decided to set out on his own. On his first solo album, 1993's Return of the Boom Bap, he worked together with producers DJ Premier, Kid Capri and Showbiz, the latter providing the track "Sound of da Police". His second album, 1995's KRS-One, featured Channel Live on "Free Mumia", a song in which they criticize Civil Rights activist C. Delores Tuckeramong others. Other prominent guest stars on KRS-One included Mad Lion, Busta Rhymes, Das EFX and Fat Joe.

In 1991, KRS-One appeared on the alternative rock group R.E.M.'s single "Radio Song", which appeared on the band's album Out of Time, released the same year.^[22]

In 1992, Bradley Nowell from Sublime featured an acoustic song named "KRS-One" with his voice and DJ's samples.

In 1995, KRS organized a group called Channel Live, whose album Station Identification he produced most of, along with Rheji Burrell and Salaam Remi.

In 1997, KRS surprised many with his release of the album I Got Next. The album's lead single, "Step into a World (Rapture's Delight)", containing an interpolation of punk and new wave group Blondie, was accompanied by a remix featuring commercial rap icon Puff Daddy; another track was essentially a rock song. While the record would be his best-selling solo album (reaching #3 on the Billboard 200), such collaborations with notably mainstream artists and prominent, easily recognizable samples took many fans and observers of the vehemently anti-mainstream KRS-One by surprise.

In August 1997, in an appearance on Tim Westwood's BBC Radio 1, KRS-One criticized the station for not playing underground hip hop while also crediting Westwood for his promotion of hip hop over time. KRS-One said that Jive Recordsand Radio 1 did not support him, but finished by saluting Westwood with "you know you're my man".

In 1999, there were tentative plans to release Maximum Strength; a lead single, "5 Boroughs", was released on The Corruptor soundtrack. However, KRS apparently decided to abort the album's planned release, just as he had secured a position as a Vice-President of A&R at Reprise Records. The shelved album was again scheduled to be released in 2008, but ultimately an unrelated album entitled Maximum Strength 2008 was released in its place. He moved to southern California, and stayed there for two years, ending his relationship with Jive Records with A Retrospective in 2000.

In 2000, KRS-One and DJ Tomekk made a video for their single Return of Hip-Hop with German rappers Torch and MC Rene, in which hip-hop was revived by hospital staff. The song stayed in the German charts for nine weeks.^[23][24]