Parkinson pipped fellow Brit Martyn Walton to second place at the Baku Aquatics Centre, recovering from last position at the halfway stage to finish in a time of 2:01.94.
It was the 16-year-old's first final of the week having watched many of his teammates already enjoy success in the pool, and he admitted that he felt more pressure to do well despite being the slowest qualifier in the medal event.
After receiving his silver, Parkinson spoke to Sports Mole about what he described as a "dream moment".
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Congratulations Jarvis, can you sum up how you're feeling right now?
"Over the moon. I didn't expect that at all, I went in in lane eight. To be honest I went in with an open mind, thinking it was going to be a close race, I might as well just attack it and see what happens. It went exactly right and I came away with silver."
What were your hopes going into the race having reached the final as the slowest qualifier?
"Well I know my PB was 2:02 before I went into it, I got 2:03 in the qualifier and I knew that I could take a little bit more off. I came away with a 2:01 and I was like 'God!' I'm just happy with a 2:01, to be honest."
Was it a bit of a surprise to look up and see yourself in second place?
"Yeah. I wasn't expecting anything like silver. I was just expecting to come out out of breath and a bit sore. But out of breath, a bit sore and a silver medal is a bit of a step up."
You shared the podium with bronze medallist teammate Martyn Walton - does that make it even more satisfying?
"Yeah. Me and Martyn over the last few years have had some good races in the 200m IM. People think of him as a freestyler but he's a bit of an undercover IM swimmer. He's not too bad! We've both touched and Martyn realised he was third and I realised I was second.
"We both looked at the person who was in the other position and we both realised that we were second and third. We both looked across at each other and gave each other a thumbs up. I wouldn't say it was a dream moment but it came... it was actually! It's more than what I wanted."
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You've had to wait until the third day of swimming action here to take part in your first final - is that frustrating for you, particularly with Team GB doing so well?
"Yeah, it put a little bit of pressure on me to be honest, everyone was just like 'you're going last in the final, there's no pressure, so just go in and see what you can do'. But every time someone said 'no pressure' there was more pressure.
"I was just thinking 'I've got to do well now!' I'm surprised at what I did and coming back from seventh at the 100m to second at 150m, and finished off second as well."
What does this do for your hopes in the 400m individual medley on Saturday?
"Well, I always say the 200m is my better event - my coach disagrees, he thinks the 400m is my better event. As I said, as with this race or the whole thing, I'm going in with an open mind.
"I'm going to use it as an experience and a stepping stone in my career. I'm going to go in and see how it goes."