Brown made his official WWF debut in 1997 as a member of Faarooq's Nation of Domination heel stable as one several non-descript people in suits that accompanied the group to the ring. During this time, his most notable moment was when Amhed Johnson slammed him onto the roof of a car during Shotgun Saturday Night. After the King of the Ring 1997, Farooq fired the members of the Nation, except for D-Lo, who was later joined by Ahmed Johnson (later replaced by Rocky Maivia), Kama Mustafa, and Mark Henry. In early 1998, the group turned on Faarooq, allowing Maivia to assume leadership, now going by the name "The Rock". Kama also changed his name to "The Godfather" and began portraying a pimp character. D'Lo and Henry eventually turned on both Rock and Godfather separately, moving into a feud with the Rock before finally branching out as a moderately successful tag team, later turning face along the way. Prior to the face turn, Brown had started wrestling with a chest protector, supposedly for a torn pectoral muscle sustained in a match against Dan "The Beast" Severn. Instead, he used the chest protector to his advantage, making his finishing move, the Lo Down, more effective. In 1998 he had a tremendous feud with X-Pac over the WWE European Championship. His career peaked when he held the European and Intercontinental Championships simultaneously during a feud with Jeff Jarrett and Mark Henry. This feat was only duplicated by Jeff Jarrett, Kurt Angle, and Rob Van Dam, all of whom became World Heavyweight Champions in some form since said double reigns.
Brown was involved in inadvertently ending the career of Droz on October 5, 1999 when a running powerbomb was botched due to Droz' baggy shirt. The match was to be aired on the October 7 edition of SmackDown!. The match was never aired and Droz suffered a severe neck injury, leaving him a quadriplegic.
During the rest of the year and into some of the next, Brown became an ally of former fellow Nation member The Godfather, emulating his dress and walking motions. The teaming ended when Brown turned heel on the Godfather.
Brown then formed a tag team in July 2000 with Chaz named Lo Down. The team mostly wrestled on Sunday Night Heat and WWE Jakked / Metal. Shortly after the team formed, Tiger Ali Singh joined the team to become their manager. The tag team then came dressed towards the ring in Sikh attire and took on a gimmick very similar to Tiger's. The team was removed from WWF TV in January 2001. Chaz and Singh were later released by WWE while Brown stayed in WWE's developmental territory. Brown returned to TV on the April 28, 2002 episode of Heat, losing to Eddie Guerrero.
For the rest of the year, Brown mostly wrestled on Heat, did a little bit of commentary on the show, and even started a brief feud with Raven. In late 2002, Theodore Long retired as a WWE referee and managed D'Lo, who had complained about acts of racism being talked about on him during his matches. D'Lo started Long's group Thuggin' and Buggin' Enterprises which eventually turned into a group of African Americans who worked an angle in which they felt they were victims of racism and were being held down by the "white man." With Long's managerial services, D'Lo Brown went undefeated for several weeks.
Brown faced Booker T in a losing effort on the February 10, 2003 episode of Raw. His involvement with Thuggin' and Buggin' Enterprises was brought to a close when footage was shown on the February 16 episode of Heat of Theodore Long kicking D'Lo Brown to the curb and introducing his replacement Rodney Mack. He was then released from his WWE contract on February 14, 2003.
In 2008, Brown began wrestling in a number of dark matches for WWE. On June 5, WWE announced that Brown had been signed to a contract, and he began working more dark matches for the company. He made his television return on the July 21, 2008 edition of Raw, defeating Santino Marella. Following this, Brown's appearances on television became more sporadic, and on January 9, 2009, it was announced on WWE.com that he had been released from his WWE contract after a major cost-cutting spree.