Ohio laws are actually pretty liberal as it relates mere players. The only possible code that would be violated by playing online would be if one is doing so publicly or engaging in sportsbetting. The definition of bookmaking is a little bit strange as it can also include the act of placing bets with a bookmaker. Illegal gambling is otherwise only such in the event that it is done publicly.

For those reasons...
... if you are not operating an unlawful gambling enterprise, by the letter of the law, you have nothing to worry about in the State of Ohio.
With nearby Pennsylvania recently legalizing and regulating online gambling via its land-based casinos, it wouldn’t be surprising to see Ohio do the same thing within the next couple or few years, perhaps even as early as next year. It’s difficult to say, if they did, whether the owners of racinos could get on board with it, or if it would be restricted to just casinos. Either way, the casinos in Ohio are pretty spread out, so they might see it as a way to maybe get a piece of the market whose nearest land casino is in a different state.
One other caveat on the Ohio law regarding players is that they cannot engage in illegal gambling if they are doing it as:
4) Engage in betting or in playing any scheme or game of chance as a substantial source of income or livelihood;
Which you can read more about here on our Ohio restrictions page:
The law doesn’t say what constitutes, “Substantial,” but it is definitely meant to refer to players as they are completely separate codes that illegal operators fall under.
There have been a number of illegal gambling operations in the state that have been broken up throughout the years, but every single one of them focused on some sort of physical gambling enterprise taking place in the state ranging from illegal machines to bookmaking and a high-stakes poker ring.
As far as we can tell...
...nobody has ever been arrested or charged with, “Gambling,” for acting as a mere online player, professional or otherwise. If you’re not playing on some sort of basis that results in substantial income, then you’re clear as a matter of the law.
For this reason, the majority, if not all, online casino operators who do business in the United States will also extend their services to residents of Ohio.