Upon his return to OVW, Hennigan was put into a feud with his former partner Matt Cappotelli. During the course of the feud Melina was brought in to the company as Nitro's ex-girlfriend and an ally of Cappotelli, only to turn on him and side with Nitro. Not long after, Nitro and Melina were joined by Joey Mercury, forming the stable MNM. MNM wrestled in OVW for around a year, holding the OVW Southern Tag Team Championship once, before being called up to the main SmackDown! roster in April 2005.
[19]
In their first match for the brand, they won the WWE Tag Team Championship from Rey Mysterio and Eddie Guerrero. MNM held the titles for three months, having successful titles defenses against the teams of Mysterio and Guerrero and Hardcore Holly and Charlie Haas, before dropping them to the Legion of Doom (LOD) at The Great American Bash. They won the titles again in a four-way match defeating The Mexicools, William Regal and Paul Burchill, and LOD, but lost them to Mysterio and Batista days before Armageddon in December. Due to help from Mark Henry, MNM defeated Mysterio and Batista in a rematch on December 30 to win the championship for the third time. They began a rivalry with the team of Paul London and Brian Kendrick that lasted over three months, until they dropped the championship to London and Kendrick at Judgment Day in May, with the storyline leading to Nitro and Melina suddenly turning on Mercury after the match, breaking up the group. Later that night, Melina and Nitro were booked off the SmackDown! brand by having the General Manager, Theodore Long, "fire" them.
The next week Nitro, along with Melina, debuted on the Raw brand in a loss to WWE Champion John Cena. Hennigan was immediately placed in the WWE Intercontinental Championship picture, beginning his first reign at Vengeance in June defeating champion Shelton Benjamin in a Triple Threat match also involving Carlito. Hennigan held the belt for four months, feuding with several challengers before losing it to Jeff Hardy on the October 2 episode of Raw. Nitro recaptured the Intercontinental Championship from Hardy on November 6 when the General Manager for the night, Eric Bischoff, restarted a match that Nitro lost by disqualification. The next week, however, Hardy won the title back.
In addition, Hennigan was featured in a sporadic feud with John Cena throughout 2006. The feud was unique in that it also involved non-wrestler Kevin Federline, who appeared on the October 16 episode of Raw. Federline was then, in storyline, trained by Nitro for a match with Cena, which he won after interference from Umaga.
In November, MNM reunited on an episode of Raw to accept an open challenge from The Hardys (Jeff and Matt Hardy) at December to Dismember, a match that they lost. MNM and the Hardys feuded across the brands throughout December, with the feud intensifying after Mercury was legitimately injured at Armageddon in a four-way ladder match. Mercury wrestled Matt on SmackDown!, while Nitro continued to feud with Jeff for the Intercontinental Championship on Raw, including a steel cage match at New Year's Revolution. MNM lost to The Hardys at the Royal Rumble, and again at No Way Out in February which ended the feud. MNM continued on and off as a team until Mercury was released from WWE in March 2007.
Without Mercury, Nitro's association with Melina was played down as she began competing for the WWE Women's Championship. Nitro was paired up with Kenny Dykstra, until the 2007 WWE Draft, during which Nitro was sent to the ECW brand and Dykstra to SmackDown!.
Hennigan made his ECW debut on June 19 with a win over Nunzio, and the next week, at Vengeance: Night of Champions, took the vacant ECW World Championship in a match against CM Punk, when he was called upon to replace the missing Chris Benoit.
A few weeks after getting the title, Nitro's name was changed to John Morrison and his gimmick was tweaked to be even more conceited and self-aggrandizing, modeled after Jim Morrison, to whom Hennigan bears a resemblance. After defeating CM Punk again at The Great American Bash, he began taking part in a "15 Minutes of Fame" segment on the weekly ECW on Sci Fi television program, where if a wrestler could either defeat him or last 15 minutes without being defeated, they would earn a title shot. The first wrestler to do so was CM Punk, which set up another match between the two at SummerSlam. Morrison won by illegally using the ring ropes for leverage. The next week, Punk again became the number one contender; this time, however, Punk won the championship. Hennigan was then suspended for thirty days for violating WWE's Wellness Program, renewing his feud with Punk upon his return, as well as competing against The Miz for the number one contendership to the title.
Though rivals, Morrison and The Miz were placed in an ad hoc team on the November 16 episode of SmackDown!, and were booked to take the WWE Tag Team Championship from the imploding team of Matt Hardy and Montel Vontavious Porter. At Survivor Series, Morrison and The Miz were both defeated by CM Punk in a triple threat match for the ECW Championship. After the defeat, the rivalry aspect of Miz and Morrison's relationship faded, as they were now portrayed as trusting friends. In February 2008, Morrison and The Miz were given a streaming segment on WWE.com named The Dirt Sheet in which they mocked other wrestlers and facets of pop culture. The team had many successful title defenses over the next few months, before dropping the titles to Curt Hawkins and Zack Ryder at The Great American Bash in a fatal four-way match which also featured Jesse and Festus and Finlay and Hornswoggle. Neither The Miz nor Morrison were pinned, as Hawkins pinned Jesse to win the titles.[63]Afterwards, they started a feud with Cryme Tyme (Shad Gaspard and JTG) through each team's Internet show, which then transitioned to matches on Raw and at Cyber Sunday.[http:// [64][65][66]] After winning the Slammy Award for Best WWE.com exclusive earlier in the day, Morrison and The Miz won the "Tag Team of the Year" Slammy Award on the December 8, 2008 episode of Raw.[67] On December 13, Morrison and The Miz won the World Tag Team Championship from CM Punk and Kofi Kingston at a Raw live event.[68] Morrison and the Miz engaged themselves in a feud with The Colóns (Carlito and Primo), who were the reigning WWE Tag Team champions which resulted in both teams defending their respective championships successfully in separate matches. Their feud culminated in a tag team lumberjack match at WrestleMania XXV where both titles were on the line, but it was The Colóns who would unify the championships with a win.[69] As part of the 2009 WWE Draft on April 13, The Miz was drafted to the Raw brand to split up the team, and, as a result, Miz attacked Morrison.
On April 15, 2009, Morrison was drafted to the SmackDown brand as part of the 2009 Supplemental Draft. In Hennigan's first match back for the brand, on April 17, he defeated R-Truth. On the May 1 episode of SmackDown, Morrison defeated Shelton Benjamin, and then engaged in a backstage fight with Chris Jericho, after Jericho slapped him, thus beginning a transformation into a fan favorite. At Judgment Day, Morrison defeated Benjamin in a rematch. On the July 31 episode of SmackDown, Morrison had his first World Heavyweight Championship match against champion Jeff Hardy, but failed to win the title. On the September 4 episode of SmackDown, Morrison defeated Rey Mysterio to win his third Intercontinental Championship. On December 4, 2009, He Lost To Drew McIntyre In A Non-Title Match, With McIntyre Slamming His Head On The Metal Railing Under The Ring. At TLC, he lost to McIntyre by a thumb in the eye, with him becoming the new Intercontinental Champion.