The station originally began broadcasting in 1962, as a carrier current station. By 1966, KALX (then known as Radio KAL, the call letters being derived from Berkeley's nickname "Cal") had moved from Berkeley's dormitories to Dwinelle Hall on campus, and Berkeley administrators began investigating the possibility of applying for a broadcast frequency for the station. KALX received its broadcast license and made its first FM broadcast, with 10 watts of power, in 1967. The studio in the basement of Dwinelle was modest, a small chamber sequestered off from a sizable library of albums.
In the 1970s, KALX was taken off the air for a short period by the faculty oversight Radio Policy Board after the station manager and friends had abused their use of university automobiles for private use and run up large bills for long distance phone calls to their contacts in Los Angeles and elsewhere. After an investigation, the station was put back on the air with new management.
In 1981, the station began a successful fundraising drive to boost its power level to the present-day 500 watts, a level that was reached in 1982.
The arrangement lasted only sixteen games. One month into the season, Finley decided to keep the Athletics in Oakland and awarded the broadcast rights to KNEW. Nonetheless, the setup made the A's a laughingstock in the Bay Area. At the time, KALX only operated at 10 watts, rendering it practically unlistenable more than 10 miles from Oakland Coliseum. This led one fan to joke about the A's radio network stretching all the way to Hawaii by asking, "Honolulu? How about here?
KALX has provided a training ground for numerous individuals who have had careers in television and radio. These include Lisa Stark of ABC News, Sarah Wallace, Andrew Reimer, Kristen Sze, Bob Sarlatte, and Robert "Doc" Pelzel.