Parnell, 50, inherited the governor's office in 2009, when he was lieutenant governor and Gov. Sarah Palin resigned during her first term. He won election to the office in his own right in 2010.
During his tenure, Parnell's legislative agenda has focused, in part, on family and fiscal issues. He championed efforts to crack down on domestic violence and sexual assault in the state, and he made record budget cuts in 2011 after legislators failed to keep to a spending limit he had proposed as financially responsible. He has been an outspoken supporter of a state-funded scholarship program that he sees as key to helping raise expectations for students and changing Alaska's public education system.
Perhaps his biggest win came just weeks ago, with passage of a tax cut on oil companies. Parnell had proposed changes of some kind to the tax system since 2010, his first legislative session as governor. His victory this year came months after Republicans seized control of the Senate from a bipartisan coalition. That put Republicans in charge of the House, Senate and governor's office.
There is a citizens' effort under way to try to repeal the tax cut, which critics believe will be disastrous for the state's budget.
Parnell is an attorney and former state legislator who, in-between stints in public service, worked for ConocoPhillips. In 2008, he challenged U.S. Rep. Don Young in a three-way race for the Republican nomination for U.S. House, coming in a close second.
Walker said he was surprised by Parnell's decision to seek re-election.
"I thought he'd given everything he could give away to the oil industry. ... I'm not sure what's left for him to give away, so I'm surprised he's going to go another round," Walker said. "I think Alaska needs a governor that puts the office and puts Alaskans first."
Follow Becky Bohrer at http://twitter.com/beckybohrerap .