The 28-year-old was the National League's Player of the Month after he led the league in slugging percentage (.750) while hitting nine home runs and driving in 18 runs in April.
Much has been made of Johnson's hot start, and though the power certainly was more than expected, success is something he has had his share of in the big leagues.
In 2007 and 2008, he was one of the more productive second basemen in the league, compiling on-base plus slugging marks of .831 and .795 for the Braves.
A wrist injury contributed to a 2009 that was disappointing for Johnson as he slumped to .224 and was supplanted at second base by rising prospect Martin Prado.
That led to the Braves deciding not to tender Johnson a contract. It did not take long for D-backs GM Josh Byrnes to get on the phone with Johnson's agent.
"I started with him when he was in high school," Byrnes said this spring. "He was a top pick out of high school. He's always hit, and we watched him through the Minors. We just felt like he had a down year, so we were happy to get him."
This spring, fellow newcomer Adam LaRoche, who played with Johnson in Atlanta, told anyone who would listen that the D-backs' decision to sign Johnson was a smart move.
"This will be a chance for him to really put it together over a full season and see what he's capable of," LaRoche said. "I think everyone has always known he could do it, but he hasn't really been in the right spot to play every day. There's something to be said for coming into camp and knowing you're the guy and the organization is confident in you."
Johnson is one of the more accessible players on the team, but ask him to talk about his hot start and you can tell by the look on his face that he would rather talk about anything else.
"I don't like talking about the past, good or bad," Johnson said. "If you have a good month, you had a good month. What are you going to do the next four months or whatever? That's important, and that's part of the mentality you have to have in this game."
When the season started, D-backs manager A.J. Hinch had Johnson hitting seventh in the lineup, but when leadoff hitter Conor Jackson went down in mid-April with a hamstring injury, Hinch moved Johnson to the leadoff spot.
Johnson has continued to hit and figures to be at the top of the lineup for the foreseeable future.
"It's another example of how he's taken advantage of an opportunity," Hinch said.
Although LaRoche predicted success for Johnson, he is surprised by the number of home runs Johnson has hit.
Oh, and there's one other thing that shocks him.
"The beauty of Kelly is he does all of this without a speck of athletic ability," LaRoche said. "I tell him all the time, 'Making the most out of nothing is what you do.'"