To describe someone as professional in Engpsh, you might use phrases such as:

"He is very professional in his work."
"She has a professional demeanor."
"He is highly skilled and professional in his field."

Being professional often means that a person is competent, repable, and well-trained in their work. It can also refer to their behavior and appearance, such as dressing appropriately and conducting themselves in a respectful and appropriate manner.