He made his WWE debut on the October 30, 2003 episode of SmackDown! and was picked with the returning Nathan Jones by then General Manager of SmackDown!, Paul Heyman, to join Team Lesnar, which consisted of Matt Morgan, Nathan Jones, Brock Lesnar, Big Show and A-Train. It was hinted that Matt Morgan and Nathan Jones would be a tag team, but their only tag team match was at the 2003 Survivor Series pay-per-view, when they took on Team Angle (not the stable introduced one year earlier, but a one-off combination of five wrestlers). They lost to Team Angle in a ten-person elimination tag team match at 2003 Survivor Series. Matt Morgan was eliminated by Kurt Angle after Kurt Angle gave Matt Morgan an Angle Slam. Matt Morgan was then used to make run-ins along with the other members of Team Lesnar, helping Brock Lesnar against his opponents.
Very soon thereafter, Nathan Jones quit WWE, so Matt Morgan occasionally teamed with Brock Lesnar. He teamed up with Brock Lesnar, Big Show, and Rhyno in a four-on-two Handicap match against Chris Benoit and John Cena on the January 22, 2004 edition of SmackDown!, in a losing effort. On January 25, 2004, he competed in the 2004 Royal Rumble match, in which the winner would get a title shot against their brand's champion at [XX|WrestleMania XX]; he got rid of The Hurricane but was eliminated by Chris Benoit, who would go on to win the match and the World Heavyweight Championship at WrestleMania XX.
Two nights later, Paul Heyman announced a second Royal Rumble match to air on television. This shortened match would only feature the Royal Rumble match participants from the SmackDown brand. But during the announcement, he claimed (accurately) that Matt Morgan had sustained a shoulder injury and he would be replaced by eventual match winner, Eddie Guerrero
Morgan returned to the WWE on the April 21, 2005 episode of SmackDown!, with a new gimmick as a stuttering big-man who was defensive over his speech disorder, and quickly defeated a then-unknown jobber, Zack Ryder. On the May 19 episode of Smackdown!, he allied himself with Carlito Caribbean Cool and became his "backup". Morgan helped Carlito defeat The Big Show at Judgment Day, using Lesnar's former finisher, the F-5. This partnership ended when Carlito was drafted to Raw, and Morgan was subsequently released by WWE on July 5, 2005. His last match in the WWE was on the July 7, 2005 episode of SmackDown! against William Regal, although technically the match never took place as Morgan was attacked by The Mexicools before Regal ever got to the ring.