ANCHORAGE, Alaska (AP) - Independent candidate Bill Walker has won the Alaska governor's race, following an aggressive challenge to Republican Gov. Sean Parnell that included joining campaigns with a Democratic rival. "I am beyond myself with excitement," Walker said Friday evening. It has been a long, long journey with a whole lot of Alaskans at my side. Walker grabbed a slim lead on election night, but the race was too close to call while absentee and questioned voters were counted this week. Walker won Friday when it became evident that Parnell could not overcome Walker's lead. Walker stopped short of an outright claim of victory, saying he wants to study districts where thousands of remaining ballots remain uncounted. Parnell's campaign spokesman, Luke Miller, said Friday evening that the campaign was reviewing the returns and he had no immediate further comment. Walker, an attorney and former mayor of Valdez, is the first candidate unaffiliated with a party to be elected governor since statehood. Walker's mentor, Wally Hickel, served a term as governor with the Alaskan Independence Party, a recognized third-party in the state, before going back to the GOP. Walker, who finished second to Parnell in the 2010 GOP gubernatorial primary, bypassed this year's primary by gathering signatures to support an outside run. But Walker didn't change his party affiliation from Republican to undeclared until forming a "unity ticket" on the November ballot with Democrat Byron Mallott as the candidate for lieutenant governor. Mallott won the Democratic nomination for governor in August, but a Walker-Mallott ticket was seen as more competitive to Parnell, who ran with Anchorage Mayor Dan Sullivan, a fellow Republican. Walker and Mallott joined forces in early September at the urging of labor interests and others. A major issue for Walker has been a natural gas pipeline project. Walker advocated for one for years but has taken issue with the process for pursuing one set up by Parnell's administration and approved by the Legislature, which involves the North Slope's three major oil producers and TransCanada Corp., which would own at least part of the state's interest in the pipeline and gas treatment plant. Walker vowed not to start over and to see a project through, but he also said Alaska needs a greater say than it currently has. Parnell accused Walker of having no specific plans and contradictory views, such as saying Medicaid and education would be looked at, with other areas, for possible spending cuts, while also supporting Medicaid expansion. Parnell faced sharp criticism in the lead-up to the election over his administration's handling of allegations of sexual assault and other misconduct within the Alaska National Guard. Parnell said he and his staff followed up on every allegation they received. Parnell has served as governor since July 2009, when Sarah Palin resigned, and he won election in his own right in 2010 with Lt. Gov. Mead Treadwell. In October, Palin snubbed her former lieutenant governor in his bid for re-election, endorsing Walker over Parnell, who championed the dismantling of increased oil industry taxes that were a signature part of Palin's time as governor. If Parnell had won re-election, he would have been poised to be the second-longest-serving governor in Alaska since statehood. The longest-running governor was Democrat William Egan, who served three four-year terms, the first two terms consecutively until the mid-1960s. Egan won a third term in 1970.