What is now MPBN dates from the 1992 merger of WCBB, the PBS member station for most of southern Maine, with the original MPBN radio and television stations operated by the University of Maine.

On November 13, 1961, WCBB signed on from Lewiston as the first Educational television station in Maine. It was a combined venture of Colby College, Bates College, and Bowdoin College. Two years later, WMEB-TV signed on from UMaine's campus in Orono, near Bangor. Over the next decade, UMaine signed on three other stations across the state, as well as several translators. These stations formed the original MPBN network. One of these stations was WMEA-TV in Biddeford, near Portland; however, it was (and still is) practically unviewable over the air in Portland itself and points north. UMaine brought public radio to the state in 1970, when WMEH signed on from Bangor. Five other stations signed on over the next decade.

As part of the merger, all of the stations' licenses were transferred to a new community-owned entity, the Maine Public Broadcasting Corporation. MPBN's Bangor stations, WMEB-TV and WMEH radio, became the flagship stations. The television stations adopted the on-air name "Maine Public Television", but dropped this in favor of "Maine PBS" in 1998. The radio stations became known as "Maine Public Radio". In 2006, they reverted to the "MPBN" moniker.

Following the merger, on July 1, 1992, WMEA-TV became the flagship station for a secondary PBS service, Maine Public Television Plus; unlike the main network, this service expanded its over-the-air reach through the use of low-power repeaters—W39BQ in Lewiston, which signed on January 1, 1994, and W30BF in Bangor, which launched on April 16, 1994. Cuts in federal funding led to the elimination of MPT Plus on June 30, 1996; WMEA and W30BF then reverted to carrying the primary Maine Public Television service (though the latter station was sold in 1999 and is now JCTV affiliate WCKD-LP), while W39BQ eventually ceased operations.