No, this isn't a medieval style of knife.

Medieval knives broadly have two kinds of handles, "whittle tang" and "scale tang". A whittle tang is a narrower iron tang which is secured in a hole in the handle - it can either be socketed in and glued in place, or it can be long enough to pass fully through the handle and get bent/riveted over the butt. A scale tang is a wider tang to which scales are riveted/glued to bulk up the handle. In both cases, there was a further handle attached to the steel/iron of the tang itself. That handle would commonly be wood, but could also be bone, antler or horn. On nicer examples, the handle might have metallic bolsters/liners or even be made entirely of a metal like bronze/latten.

Here are a few examples, mostly from the collections of the Museum of London:

• Saxon/Viking knife blade. This short seax would have been glued into a wooden or horn handle. A few potential traces of what might be the wood are left on the tang.
• Late medieval knife blade and sheath. This is another whittle tang blade, found in the Thames still with part of the original leather sheath and wooden handle.
• Late medieval knife blade. This knife had a scale tang, and remains of the wooden handle scales are still riveted to the blade.
• Late medieval knife with copper alloy handle. This is a much fancier example, with a well preserved handle of copper alloy cast onto the iron tang of the knife.

I'm not aware where and when the style you're asking about does come from, but my suspicion (and it's only a suspicion) is that this style gained popularity because it's easy for a blacksmith to make as a demonstration piece in a modern "renaissance faire" type context - you do the forging and maybe a bit of grinding, but you don't need to learn additional skills or keep additional tools on hand when you're making cheap pieces as demos and for sale.