Why uncharacteristically? Trump doesn't smoke or drink or use drugs? It is certainly within Trump's character.
He actually does seem to have smoked and might still light up cigars every now and them, as probably many of his friends do. Check for example a clip from his recent WSJ interview. His daughter Ivanka as well as his first wife are smokers.
After all, he is 69 years old so his best young adult years were during the American golden age of smoking, 1950s-60s, when even cartoons featured cigarette ads, when doctors would offer a cigarette to their their patients in their office and recommended brands on TV.