There wasn't "journalism" in the common sense back in the Middle Ages. Information was either transported by written or oral means. Royal courts, nobles and some churches had access to parchments as a medium of information, but for most people, the only way to receive news was through the most basic of human ways: by someone else saying it out loud. This involved people who travelled frequently, such as merchants, taxcollectors, pilgrims, etc.
You specifically asked about "if a knight won a tournament, would he be "interviewed"?" I think I can speak of something similar. The example/illustration I am going to describe is related to medieval Hungary, but such phenomenon wasn't restricted to this particular country.
Near the end of the Late Middle Ages the Kingdom of Hungary was besieged by the mighty Ottoman Empire for around 150 years. The kingdom was largely a battlefield during the time, with the Ottomans and the Habsburgs playing a very long and bloody tug of war on its soil, with fronts frequently moving, castles falling, being rebuilt, etc. Life was hard back then, so the passing of information was quite important.
Wandering minstrels (I use "minstrel" in the sense that someone who sings and plays musical instruments) were a key source of information among the common population at the time. What these people did is they either were actually present during battles (meaning they were inside sieged castles for example), or arrived shorty after the battles/sieges were decided, and "interviewed" the people participating in them, who were eager to tell their "story". Then he made a "historical song" (históriás ének) about the events and in his next place of travel that song was performed to another audience. Of course such wanderers couldn't reach all the places, but the people who had heard their songs in the first place could pass them on easily.
One of the most famous Hungarian wandering minstrels of this time was Sebestyén "Lantos" Tinódi (in original Hungarian name order: Tinódi Lantos Sebestyén) where the "lantos" nickname literally means "lute-player". He was among the more "high-profile" ones, he appeared frequently in noble courts and even the contemporary Palatine (Nádor) of Hungary (the highest office just below the King) recognized his merits.
As an illustration, you can listen to a short, 1 minute excerpt from one of his songs: https://www.youtube.com/watch?v=6h-2QBOjHC8
The song is in Hungarian, but you can clearly hear that the instrument part is quite simplistic; the song's primarily aim was to deliver information (singing/speech).