Aside from freelance web design, my first "real" work was a game service provider (GSP) I cofounded with a couple friends in 2013. GSPs give customers an easy way to set up a multiplayer server for various games and play with their friends. We focused on Minecraft, which was at its height of popularity in those years.
It was just the three of us, so we all took turns doing marketing, answering customer support and live chat, troubleshooting server issues, and doing general "sysadmin" work. Initially we hosted users on rented servers, but later on bought and colocated (rented rack space space in a datacenter) physical servers. I have fond memories of recieving and booting up our first PowerEdge R710, and being able to hear it on the other side of the house.
We used off-the-shelf software initially, but later diversified into a more capable custom control panels and billing system. To my knowledge we were the first GSP that was able to bill by utilization or by hour, though this never really caught on in the industry.
In early 2014, we sold the company to a competitor, and shortly thereafter I joined MCProHosting.