Democrat Mary Burke's first ad attacks Gov. Walker's record on job creation, while praising her background with bicycle maker, Trek.
Burke is expected to be the Democratic nominee to face the incumbent Republican governor in November.
In her ad, she also claims that Wisconsin's highest unemployment rate during her tenure was 4.8 percent, while it stands at 6.2 percent under Walker. Burke served as commerce secretary under former Gov. Jim Doyle.
Walker's campaign has not yet released any campaign ads, but the Republican Governors Association has paid for two that have been running. Both criticize Burke for her time in the Doyle administration, blaming it for jobs Wisconsin lost during the recession.