If you're looking to become an Usher, job board databases are a good place to start. If the arena you're interested in is looking to fill an opening, they'll likely have a listing posted on a few job boards. You can also look for a "careers" page on the arena's website and apply there.
Whether it is a baseball, soccer, or football game sports arena, all these will want to hire fans of the home team first before they can consider other people. Hence, the best way to get yourself a chance to work as an usher at a sports arena is to start off with being a fan then registering for their fan forums. Most of the job openings,, whether it is to hold paraphernalia at a sports event, part-time event security, or crowd safety management, all these jobs will be advertised through the fan forums first before the messages can be shared with people on other platforms. Alternatively, you may use your networking skills to help you get a job as an usher at a sports arena. If you are a regular attendee of events at the arena or you know a few people that work within its ranks, you can put your application forward and ask to be hired as an usher. Ensure to illustrate excellent interperosnal skills to help you stand out from other candidates.