He had been head of the Government Accounting Office since 1998, and was a voice against unrestrained government spending and entitlement explosion.

Walker was a regular, and respected, witness on Capitol Hill, testifying on issues ranging from how to rein in the spiraling U.S. debt to the turmoil in Iraq. Last September, Walker told Congress the Iraqi government was “dysfunctional.”

Under Walker’s leadership, the GAO filed suit against Vice President Richard Cheney, seeking details on meetings he held early into the Bush administration on input from private groups on energy policy. After a federal court ruled GAO could not force Cheney to provide the information, GAO decided not to appeal the ruling, angering many Democrats.

Walker repeatedly urged Congress to waste no time in reforming massive government programs, such as health care for the elderly, which will grow significantly as the U.S. population ages.

“The picture I will lay out for you … is not a pretty one and it’s getting worse with the passage of time,” the blunt-talking Walker told Congress more than once.

Basically he was a fiscal thorn in the side of both parties, which isn’t a bad thing to have around Washington. Here’s an interview he gave to Glenn Beck back in January. It’s scary stuff.

He’s leaving GAO to head up a foundation that focuses on fiscal restraint and sounding the alarm about the federal debt.