"As governor, I'll pay my share toward my retirement because everyone should pay their own way, including me," Walker said during the campaign.
Lt. Gov. Rebecca Kleefisch made the same pledge and also didn't pay as promised.
Walker's pay stubs provided Friday in response to the AP's open records request made in September had details about his pension payments redacted. But Walker's spokesman Cullen Werwie said the governor did not start paying the full cost until August, when the state law he pushed required elected officials and other state employees to contribute more.
The requirement that state workers pay their 5.8 percent contribution was part of Walker's bill that also took away nearly all collective bargaining rights from most public employees.
If Walker had fulfilled his campaign promise, he would have been paying his pension costs during that fight in February and March.
Werwie did not have an explanation for why Walker didn't pay until the law forced him to. The law required Walker and other elected officials to make payments of 6.65 percent of their salary starting in August. That goes up to 7.05 next year.
