You can, but if you don’t have years of experience, you won’t get good shifts or make much money. Instead, you’ll stand around, not doing much, and earning even less.
If you’ve never worked in a bar and then apply for a bartending job, you’ll likely first be a barback. Barbacks lug the heavy buckets of ice, clean up spills, and usually only make minimum wage. And no tips.
But if you want to jump into the role of bartender and make bank, a bar owner will see your professional training from American Bartenders School as a major asset. Differentiate yourself with your training and experience.