The 31-year-old is hopeful the fierce speed and movement he's found during the limited overs series against England leads to an Ashes call up.
"I've surprised myself a little bit pace-wise," Johnson told AAP ahead of Saturday's fourth ODI at Cardiff.
"I think it's just a rhythm thing at the moment. I've lengthened my run-up a little bit and I'm running in probably at a good pace to get through the crease."
Johnson has picked up the pace while simultaneously working on accuracy.
"Being a little bit taller in my action, and that comes from being a bit stronger through my legs ... I definitely think my consistency has improved," he said on Thursday.
Johnson had two months at home to freshen up after the Champions Trophy and spent time in the gym working on his leg strength.
He's also been able to refine "little technical things" over the past 12 months since coming back from a toe injury.
"I just feel like I'm getting better and better each day.
"I'm really happy with where I'm at at the moment."
Australia head into Cardiff leading the series 1-0. The situation could have been better but for two matches being washed out.
It's feared rain could again interrupt Saturday's play but Johnson insists morale in the team is good.
"Everyone's pretty pumped about getting there and hopefully going 2-nil up," the 31-year-old said.
The fifth and final match in the ODI series is at Southampton on Monday.
The fact Johnson has been terrorising the likes of Jonathan Trott has fuelled speculation he'll be recalled for the return Ashes series in Australia.
The Queenslander's odds firmed further after Mitchell Starc was effectively ruled out of the series starting at the Gabba in November.
"It'd be nice ... but I am not focusing on it," Johnson said of a potential Ashes cap.
That said, he admits missing the England series was a source of motivation.
"Sitting on the couch watching the first ball being bowled gave me a lot of incentive to get back playing Test match cricket.
"I've never actually won one (an Ashes series). It'd be nice to be a part of that."
Australia will likely field a similar side to Edgbaston on Saturday with pitch conditions determining whether young fast bowler Josh Hazlewood retains his spot or spinner Fawad Ahmed is brought back in.
England isn't about to experiment with the series on the line.
"It's more about winning the series," captain Eoin Morgan said."Obviously, it's a good opportunity to blood young players, but we're out to win it."