Would a harness work well on a 9 month old St. Bernard?

I recently adopted a 9mo St. Bernard and she can sometimes be rowdy with her leash on. She usually does well with the leash but also will get the leash in her mouth while it is on her, chew on it and tug on it, then will jump at me. I was considring using a harness because she won't be able to chew on it while it is on her and she might be easier to control/train. Thoughts?