The 27-year-old Dawson, who vacated his IBF title to fight Johnson for a second time, outboxed his 40-year-old opponent, who was never able to get close enough to land the hard punches that made their first fight in April 2008 so tight.
Dawson, a southpaw, used his right jab to score, while keeping Johnson away. He won the early rounds with the strategy, following the jab occasionally with a hard left or a speedy combination.
Midway through the sixth round, Dawson caught Johnson with a left hand that snapped his head back, but that was perhaps the hardest punch he landed.
"I tried to use all the tools to my advantage, and that was the difference in the fight," Dawson said. "I felt like I landed the big punches when I had to."
Dawson won a disputed decision over Johnson (49-13-2, 33 KOs) in their first fight. He said he took the rematch to see how much he had grown since then.
He dominated this one, even though Johnson was the one moving forward most of the time, especially in the middle and late rounds.
Johnson stalked Dawson across the ring to connect with his right hand, trying to pin Dawson to the ropes, but he never really caught him.
"He was able to escape some of my bigger punches," Johnson said. "He didn't try to fight like he fought the first time. He basically just stayed away from me."
The two stood toe-to-toe for the first time in the 10th round, exchanging combinations. But neither seemed to be able to hurt the other.
"I wasn't really thinking about knocking Glen Johnson out," Dawson said. "I wanted to go in there and put on a good boxing match."
Dawson (29-0, 17 KOs) now awaits the winner of the Dec. 11 bout between WBC champion Jean Pascal and Adrian Diaconu.
Dawson vacated his IBF title this year after the sanctioning body refused to grant an exception to an immediate defense against Tavoris Cloud, a bout that would have generated far less money and TV interest than one against Johnson.
Johnson, a former "Fighter of the Year" in 2004, had won seven of his last nine fights, but will celebrate his 41st birthday in January.
"I don't know what else is out there for me," Johnson said. "I'll wait and see if anybody wants to put me back to work."
About 5,200 people showed up for the bout at the 16,500-seat XL Center, which is about 40 miles north of where Dawson grew up in New Haven.
Many booed when it appeared Dawson had chances to mix it up with Johnson, but instead backed off and boxed.
"I don't let that bother me," Dawson said. "They're not the ones in the ring. They've never been hit before."
Dawson entered the ring wearing a number 6 on his robe to honor slain Connecticut football player Jasper Howard. There was also a traditional 10-bell salute for Howard, who was stabbed to death Oct. 18.
On the undercard, Alfredo Angulo knocked out Harry Joe Yorgey just over a minute into the third round to take the interim WBO junior middleweight title.
Angulo knocked Yorgey down in the second round. He landed 63 percent of his power punches, including 30 of 35 in the final round, catching Yorgey with a hard left hook to end the fight.
Yorgey's camp complained he was hit twice in the back of the head in the second round and twice while he was on the ground.
