"I still have a lot left," he said. "I mean people forget I never really played much my first two years in the NFL, let alone college. So I still have a lot of burn left and haven't really been nicked up or hurt, thank God, as far as my whole career, so this is me just kind of smoothing on out, kind of like a Cadillac."
It will be curious to watch the dynamics of a Redskins backfield consisting of Johnson and Clinton Portis -- two players used to starting, both known to speak their minds and both considered by many to be in decline.
"I think people get misunderstood as far as when you come in and there's two guys that's always been starters, to come in and there's supposed to be some sort of beef, but it's not," Johnson said. "We don't even talk about football, we just joke around basically, and he goes his way and I go my way. ... We kind of complement each other. It's not, 'I'm coming here to take your spot.'
"I wouldn't come in and say I want to be the third guy or the fourth guy," he added. "I just come in to work hard and wherever they have me on the depth chart is wherever they have me."
Speaking with reporters for the first time since signing with the Skins, Johnson said all he really needs is "a coach who cares." He finished last year with the Cincinnati Bengals, but it was his off-the-field issues with the Kansas City Chiefs that have threatened to overshadow his career.
Johnson was suspended twice in his final 12 months with the Chiefs. He also posted a gay slur on his Twitter account, insulted fans and questioned the competence of coach Todd Haley.
Asked if those episodes caused him to do any soul-searching, Johnson said: "Nah, I just had to be with a coach who cares and knows what has to be done to put our team in the best situation to win. Being in that situation really wasn't the best for my career or the best for the organization."
Johnson said he was more comfortable with the Bengals and expects to feel the same way with the Redskins under coach Mike Shanahan.
"It's a trust," Johnson said. "I trust them that they would do the right thing for my career and they trust me to do what's in the best interests of the organization."
That said, Johnson wouldn't call his joining the Redskins a "fresh start."
"I mean, there have been so many fresh starts I've done had," he said. "This is more like I'm just going into a different era of my own -- pretty much coming in here and being here and trying to work as hard as I can to impress the coaches and to see where it goes from there. Being 30, your fresh starts are already gone."