Grammar and style are usually the purviews of copy editors. Although it may work a little differently from one publication to the next, the copy editor usually works on an article after the bulk of the writing and editing is complete (tasks that are, historically anyway, done by people separate from the copy editor). It is the copy editor’s job to take one final look and make sure the piece is as clear and fair as possible.
But even if you don’t think your career trajectory will land you at a copy desk, that doesn’t mean you’re off the hook when it comes to formal style. Some publications still have copy editors, but the job has shifted and even disappeared in newsrooms across the U.S. to the point that many writers must copy edit their own work. It’s important to know how to copy edit and how to read a style guide no matter what your job is within journalism.
If you end up at a place that doesn’t have copy editors, build in a little extra time in your writing and editing process and give the piece a copy-edit read. In other words, read it from the point of view of a copy editor — style guide in hand. This will strengthen your writing and make your writing more accessible to your readers.