There isn't a direct translation of the name "Greg" in Hebrew. Hebrew names are often chosen based on meaning or sound. To find a Hebrew equivalent, you'd need to consider what aspects of the name you want to capture. For example, if you like the sound, you might choose a name that sounds similar, or if you know Greg's meaning (often derived from Greek "gregarious," meaning "wakeful" or "vigilant"), you could find a Hebrew name with a similar meaning.
There's no single "right" answer.