Is it permissible for a non-Muslim to play basketball after converting to Islam?

Yes, you can embrace Islam and play basketball. Islam does not prohibit beneficial sports that strengthen the body and invigorate muscles. In fact, the body has a right to be taken care of, as the Prophet Muhammad (peace be upon him) said: "Indeed, your body has a right over you." There is no harm in playing basketball as long as it is not mixed with anything prohibited, such as gambling, uncovering of 'awrah (private parts), intentional harm, or distraction from performing prayers. There are many international basketball players who have embraced Islam. Therefore, do not hesitate to embrace Islam.