The Briton defeated the controversial American in a patient albeit relatively uneventful UFC 296 main event, outstriking his opponent and nullifying the challenger's grappling game.
The victory extended Edwards' winning streak to 12, which is one behind George St Pierre's welterweight record of 13.
Much of the build-up had been marred by some off-colour remarks by Covington during the pre-fight press conference, with the outspoken fighter making fun of Edwards' late father several times.
"This guy used my dad's murder as entertainment," said Edwards.
"It took a lot for me to calm down. I spoke to my mum and my team and shut it all down.
"After the press conference, I was crying backstage because of the rage. You can't use my dad's death."
Edwards also said he put a lot of focus on his cardio to match Covington's levels for the bout:
"I know I'm the better athlete but they kept going on about cardio so I wanted to match the cardio," said Edwards.
"I wanted to grapple with him. I'm a mixed martial artist, so I wanted to come out here and prove my case.
"I feel like I was the much better athlete and technician. He's good, a great competitor but a dirty human being."
Pimblett wins on return
Earlier in the evening, Liverpool's Paddy Pimblett made his return to the octagon after over a year out of action and secured a convincing win over veteran Tony Ferguson.
The 28-year-old looked impressive both in striking and with his ground game, dominating the early rounds and almost forcing a stoppage in the first after landing a flying knee and a flurry of follow-up punches.
Ferguson would survive but did not deliver much throughout the remainder of the contest, failing to snap a six-fight losing streak.
Pimblett himself was aiming to prove a point after looking less than impressive in his last outing against Jared Gordon 12 months ago.
"You could see I won every round, you can't dispute that," said Pimblett.
"I feel better. I'm still disappointed I didn't finish Tony, but I won every round.
"He is an absolute legend. Everyone give a round of applause to Tony Ferguson. Legend. How did he survive that first round?" he added.
