But while the England coach was delighted with the winger's performance he was also quick to highlight the team's effort in all of Ashton's tries.
"I am obviously very pleased with how Chris played today," said Johnson.
"He took his tries well. However, it was very much a team effort to get him across the line.
"Toby Flood bossed the game well at ten and Matt Banahan made a great break for Chris Ashton's fourth.
"The swan dive was only 0.1% of the conversation from the week, but of course it made up 90% of media coverage.
"I was tempted to put his number up when he scored the fourth just to see his reaction. I told him, when he came off the pitch that it was an interesting way to end a career.
"But seriously, he is playing well. His running lines are superb and he's a very smart player, despite the way he comes across. He really has invigorated the back three."
In England's biggest win in the Six Nations since 2003 against the same opponents, Johnson was happy with the overall pattern of play and the squad's development.
Despite chances that got away, notably No. 8Nick Easter's looped pass which was intercepted by Mirco Birgamasco when England had a four man overlap, the clinical nature of the performance pleased Johnson.
"We scored the try early and played a fantastic running game," added Johnson. "We took our try scoring chances and whenever we got into those positions, we executed the plays well.
"There is a cutting-edge and a consistency which was not there two years ago.
"Ben Youngs did very well and Danny Care made a good impact when he came on. The performance was typified by Jonny's (Wilkinson) tackling, it shows how much intensity is there despite being forty or so points up.
"We are now two wins out of two, but it's a long way to go in this Championship.
"It was a conscious decision to get the lads on early so that we can keep fresh legs and keep injuries to a minimum.
"We will have to control the ball better against France as we will not get away with it like we did today, especially some of our kicking from hand."