After a promising start to the season that brought two wins and a draw, Swindon hit the rocks and lost their next five games before Johnnie arrived in time for the trip to QPR.
Things did not immediately get much better and the Robins suffered a further two defeats and the club was in turmoil. Fans were calling for the head of manager Andy King and the players were not getting paid.
It was not the welcome to League football the 20-year-old might have anticipated.
"My first game was against QPR and they had lost five on the bounce before that," recalled Johnnie. "The fans were getting on the back of the team and we lost to QPR, then later we played at home against Oldham and lost that.
"It was the first time I had experienced anything like it. Oldham went 1-0 up after about two minutes and then for the whole game it was 'we want King out, we want King out'.
"It wasn't easy but we then started to get a few results to turn it around."
Fortunes did turn around and Swindon lost only one of their next seven, but the club was still engulfed by financial difficulties.
"The players weren't getting paid at one stage due to the problems there and there was a bit a unrest among the boys because of that.
"I felt a bit guilty because I was the only one being paid - when you are on loan you are still paid by Spurs. It was a bit awkward, but the lads were good about it."
Swindon were still enjoying an upturn in League form as Johnnie's three-month loan spell drew to a close. He elected to return to Spurs rather than spent the rest of the season at the County Ground as the option of a shorter extension was not available.
"It has picked up and they haven't lost a league game in seven now. They are a bit of a form side at the moment.
"It feels good to be back and it was my decision. The situation was that I could have stayed there for the rest of the season or nothing at all - I couldn't have just stayed for another month.
"It would have meant being away for another five months, so I spoke to a few people at the club and my dad and decided to come back.
"My loan ended officially last Thursday, but I came in on Wednesday, spoke to Colin and the gaffer to see what they thought and then spoke to Andy King and told him my decision."
Apart from the aforementioned difficulties, Johnnie says he has gained a lot from his spell in Wiltshire.
"It's weird first of all, but they are a great bunch of lads there and they made me feel welcome. There were a couple of London boys who I used to travel in with so I settled in well.
"It's a bit of a shock at first - the pace and the physical side of the game. I hadn't played league football before so it was difficult, but after that I settled into it.
"I'm a fairly big boy, but it is completely different to reserve football so it was hard to begin with. Once I played a few games I got used to it.
"I commuted mostly and used to stay there a couple of times a week. There was a lad from west London and I used to travel in with him mostly so it was easy.
"I played every game. I really enjoyed it and if I could have stayed for a month or two more I would of, but I just thought five months was a bit long. To be playing first team football was great."
So how was Johnnie's game during his time away from Spurs?
"I was a little bit on and off - I sneaked a couple of Man of the Match marks."
The Camden-born player says it was hard to establish any sort of rapport with the County Ground faithful, but hopes his contribution to the cause went down well.
"It was difficult. I hope I was well received but I don't really have a clue as to how they felt about me. They seemed to take to me well while I was out there and I didn't have any problems.
"They had more important things to worry about than me - it's all about results when you're down there. In the lower divisions it's all about that and not about individual players," he added, before confirming that he kept a close eye on events at Spurs.
"Of course I did. I spoke to Colin quite often and he came to a few of the games. I called him sometimes to find out how the team got on and who had my armband in the reserves!
It is that reserve side that Johnnie is now hoping to impress in enough to catch the eye of Glenn during the remainder of the season.
"I'm 20 years old now and the aim is to push on and try and get into the first team. I know it's going to be hard and I've just got to knuckle down and try and do well in the reserves. If I impress every week I hope I will get a chance sooner or later."
It was not the easiest of baptisms into League football for young midfielder Johnnie Jackson when he accepted the chance to head to Swindon Town on loan in mid-September.