How much experience in sports broadcasting do i need to have before i can work at ESPN?
ESPN, like every sports company, offers entry level jobs that don't typically require much experience (besides internships).
Getting your foot in the door and working your way up is a typical path for anyone in the sports industry.
I imagine a ton of experience is usually needed. But it's more important to develop a great brand identity for yourself so they realize they are missing out not having you. Putting that together to show consistently and persistence might only take 3-5 years.