The versatile midfielder returned to the fold at Christmas following a loan stint at Coventry and made his first team debut in the Boxing Day encounter against Portsmouth at Fratton Park. He has since made 11 first team appearances - scoring a memorable first goal in the 4-2 win over Charlton at the Valley.
"It was a boost to get it done," commented Johnnie on his new deal. "There was no rush, but it is always a weight off your mind when it is signed.
"It is settled now and I know where I am playing next season and beyond so it is nice to have that stability."
The 21-year-old, who was entering the final months of his previous agreement, admits that he did not imagine being offered a new one when he headed off to Highfield Road in November.
"I didn't think I would be offered one before. I've come back, been given a chance and have impressed to the extent that I've been offered a deal. I had more or less resigned myself to playing elsewhere, but things have changed around for me."
It has been a big season for several of the club's Academy products, as well as Johnnie making his mark, Stephen Kelly and Dean Marney have also tasted Premiership football, while Lee Barnard, Robert Burch and Mark Yeates have all been called into the first team squad.
"It's brilliant, they are my mates and it's been lovely to see them getting their chance as well," considered Johnnie. "Steo made his debut against Charlton, while Deano got his chance on Saturday - it's really good for the youngsters at the moment.
"I haven't been involved in the last couple of games and it is up to me to carry on working hard in training and reserve games. You must prove that your attitude is right and that you are good enough to get back in the side."
Johnnie Jackson says the award of a new contract last week offers him stability as he seeks to further his career at the club.