Simple:
* The journalist interviewed the mayor about the city's new budget.
* The journalist wrote an article about the recent protests.
More complex:
* The journalist's reputation for objectivity made her a trusted source of information.
* The journalist had to be careful not to reveal her sources in order to protect their anonymity.
* The journalist spent weeks researching the story before publishing it.
Figurative:
* He was a journalist in the truest sense, always seeking out the truth and reporting it without fear or favor.
The best way to use "journalist" in a sentence depends on the context and what you want to emphasize.