O'Reilly does have a background in local television news and tabloid TV. I would call him a commentator more than a journalist, as he is inclined to editorializes on the news more than break it.
Here's a bit of his professional biography from Wikipedia:
After graduating from Marist, Bill O'Reilly moved to Miami, Florida, where he taught English and history at a Jesuit high school for two years. After leaving Miami, O'Reilly returned to school, earning a Masters in Broadcast Journalism from Boston University in 1976. While attending BU, he was a reporter and columnist for various local newspapers and alternative news weeklies, including the Boston Phoenix. O'Reilly did his broadcast journalism internship in Miami during this time, and was also an entertainment writer and movie reviewer for the Miami Herald.
O'Reilly's early television news career included reporting and anchoring positions at WNEP-TV in Scranton, Pennsylvania, where he also reported the weather. At WFAA-TV in Dallas, Texas, O'Reilly was awarded the Dallas Press Club Award for excellence in investigative reporting. Then it was off to KMGH-TV in Denver, Colorado where he won an Emmy for his coverage of a skyjacking. O'Reilly also worked in Portland, Oregon, Hartford, Connecticut, and Boston. [5] In 1980, he anchored his own program on WCBS-TV in New York where he won his second Emmy for an investigation of corrupt city marshals. He was promoted to the network as a CBS News correspondent and covered the wars in the Falkland Islands and El Salvador from his base in Buenos Aires, Argentina (1982). In 1986, O'Reilly joined ABC News as a correspondent on ABC World News Tonight. In three years, he appeared on the show over one hundred times, receiving two National Headliner Awards for excellence in reporting.
WJLA, Washington, DC Inside Edition promo featuring Bill O'Reilly, 1993.
In 1989, O'Reilly joined the nationally syndicated Inside Edition, a current affairs television program (called "infotainment" by critics). He started as senior correspondent and backup anchor for British journalist David Frost, but soon took over the anchor chair when the viewers found him more appealing. In addition to being one of the first broadcasters to cover the dismantling of the Berlin Wall, O'Reilly also obtained the first exclusive interview with murderer Joel Steinberg and was the first national anchor on the scene of the 1992 Los Angeles riots.
In 1995, O'Reilly left Inside Edition to enroll at the John F. Kennedy School of Government at Harvard University, where he received a Master's Degree in Public Administration. Upon leaving Harvard, Roger Ailes, chairman and CEO of the then startup FOX News Channel, hired O'Reilly to anchor The O'Reilly Report, which aired weeknights. The nascent channel's most popular show was renamed to The O'Reilly Factor when it moved to a later time slot in 1998 since the host was the main "factor" of the show.