The station began broadcasting on March 9, 1959 as WDHF, owned by Hi-Fi systems and record store owner James deHaan. Its call sign stood for deHaan Hi-Fi. The station operated out of deHaan's store in the Evergreen Plaza in Evergreen Park, Illinois. Its transmitter and tower was in Oak Lawn, at 97th and Central. WDHF's studios and deHaan's record store moved to 102nd and Western Avenue in Chicago, in 1961.
In 1964, WDHF was sold to Federal Broadcasting Corporation for $200,000. Controlling interest in Federal Broadcasting was owned by comedian Bob Newhart. Its studios were moved to the Loop, at 108 N. State St. In 1966, WDHF was sold to the National Science Network for $427,000. In 1971, the station's transmitter was moved to the John Hancock Center on the Near North Side of Chicago. Under deHaan's, Newhart's and the National Science Network's ownership, WDHF aired an easy listening/big band format.
In 1973, the station was sold to Metromedia for $2.75 million and it adopted an adult contemporary format. The following year, WDHF adopted a top 40 format. During this era, WDHF was the local broadcaster of the weekly syndicated program American Top 40. Jim Channell, known on the air as "Captain Whammo", was a DJ on the station during its top 40 years.
On December 1, 1976, the station's call letters were changed to WMET, while retaining its top 40 format. In 1979, Metromedia flipped WMET to an AOR format. In 1982, WMET was sold to Doubleday Broadcasting for $9.5 million.
On January 11, 1985, at 3 p.m., WMET switched to an adult contemporary format. As a promotional stunt, in the days leading up to the format change the station periodically interrupted the rock programming with static and a man's voice stating "enough is enough". Ratings were poor under the new format, and the station was sold to Flint Chicago Associates for $12.5 million in early 1986.
In May 1986, the station's call sign was changed to WRXR, and it adopted an early version of what would later become the adult hits format (described as "Male Adult Contemporary" by station management), with a playlist featuring artists like The Beach Boys, The Doobie Brothers, ZZ Top and Sade. In 1987, WRXR was sold to Pyramid Broadcasting for $15 million.
Smooth jazz era
WNUA's logo as a smooth jazz station
On August 3, 1987, the station's call letters were changed to WNUA and the station adopted a format which featured new-age music and smooth jazz, along with music from R&B and rock artists that were compatible with the station's sound. WNUA's original slogan was "Music For a New Age", and New Age was the source of the station's call letters. By 1989, the station's slogan was "Smooth Rock, Smooth Jazz". "Smooth Rock" would later be dropped from its slogan. As a smooth jazz station, WNUA was a major pioneer in the format.
In 1995, the station's owner, Pyramid Communications, was acquired by Evergreen Media. In 1997, Evergreen merged with Chancellor Broadcasting. Chancellor merged with Capstar and restructured as AMFM, Inc. in 1999, and in 2000 merged with Clear Channel Communications making WNUA a Clear Channel station.
In late 2006, three Smooth Jazz personalities, WNUA's Ramsey Lewis, Annie Ashe, and Dave Koz, were tapped by Broadcast Architecture to syndicate their respective shows on its Smooth Jazz Network.
Smooth Jazz returned to the 95.5 frequency on the HD2 feed in December 2018, much to the delight of fans of the original WNUA Smooth Jazz format.
On May 22, 2009, at 9:50am, after the station played David Sanborn's "Chicago Song", WNUA stunted for 5 minutes with a ticking clock and an announcer saying "In _ minutes, 95.5 reaches its big/mega event." Along with the clock sound, they aired a recap of jingles and moments from its history as WDHF, WMET, WRXR, and WNUA. 95.5 then had a countdown from 10 to 1 switching in the middle from English to Spanish. At 9:55 am, WNUA flipped formats to Spanish hot AC as Mega 95.5. The Smooth Jazz format was picked up a few hours later by television station WLFM-LP (Channel 6), whose audio is available on 87.7 FM.
Following lackluster ratings as Mega 95.5, on June 19, 2012, after playing "Creo en Ti" by Mexican rock band Reik, WNUA shifted to a Regional Mexican format known as "El Patrón 95.5" to more directly compete with 107.9 WLEY and 105.1 WOJO. However, the station failed to improve on its ratings as Mega 95.5.