[1] Later in 2012, Dawson moved down to super middleweight, a division in which he had not competed since 2006, in order to challenge Andre Ward for his unified titles.

In what would prove to be an ill-fated move, Ward handed him his second loss as it became clear that Dawson could no longer compete at a lower weight.

His career took a temporary setback when he failed a post-fight drug test in 2004 for marijuana, which resulted in a six-month suspension from boxing.

After suffering a flash knockdown in the opening seconds of the first round, Dawson dominated the fight and pulled away on the judges' scorecards by 117–110, 117–110, and 116–111.

[6] At age 24, on February 3, 2007, Dawson won the WBC light heavyweight title against the undefeated, top-ten ranked champion Tomasz Adamek.

[7] In June 2007, Dawson defended the WBC title for the first time, in a fight with Jesus Ruiz (19–5–0), winning by technical knockout in round six.

In April 2008 as his third title defense, Dawson retained the belt by a controversial unanimous decision victory against challenger Glen Johnson.

On October 11, 2008, at the Palms Casino in Las Vegas, Dawson fought IBF light heavyweight title holder Antonio Tarver.

Dawson, who controlled the pace and landed most of the significant punches for a majority of the fight, was more active in methodically wearing out his opponent.

Dawson stated "I'm ready to give Joe the opportunity to draw the curtain on his great career in front of his family and friends and 70,000 fans," and "It's the best fight in the light heavyweight division between two undefeated champions."

Timing is everything, and to leave center stage at his peak is rare and certainly comparable to the retirements of Rocky Marciano and Jim Brown.

Dawson initially won The Ring, WBC and lineal light heavyweight titles due to a controversial TKO win, when Hopkins was unable to continue after getting thrown from a clinch.

Noteworthy to mention is a period after a middle round where his trainer, former contender Iceman John Scully, caught Dawson mentally slipping and motivated him back into focus.

On September 8, 2012, Dawson stepped down a weight division (a rarity in the sport) to take on WBA, WBC, The Ring and lineal super middleweight champion, Super Six World Boxing Classic winner and one of the universally recognized top pound-for-pound fighters in the world Andre Ward.

[19] The fight started quite cagey with both fighters feeling each other out and only exchanging single shots, with Dawson landing his jab on Ward comfortably.

In the 3rd round, a clash of heads changed the entire landscape of the fight in Ward's favour, as he seemed to have found out his opponent and proceeded to catch Dawson with some telling shots, dropping him to one knee with a right to the body and short overhand left hook.

In round 10, it all came to an end as Dawson looked to have tired from Wards' consistent battery and possibly because of the weight loss also, he was caught flush with 4 shots in a row appearing to voluntarily take a knee.

After taking the rest of 2013 off Dawson accepted a fight with journeyman George Blades, which was televised as part of the preliminary bout undercard of a Showtime event on June 14, 2014.