Knowles, who was born in Tulsa, Okla., enlisted in the Army in 1962 and joined the 82nd Airborne Division, serving in Vietnam from 1964-65, according to the National Governors Association. In 1968, he graduated from Yale University.

He moved to Alaska in 1969 to work as a roughneck at the Cook Inlet and North Slope oil fields, and opened his first of four restaurants, the Grizzly Burger, a year later with his wife Susan.

His political life began in the Anchorage Assembly, where he served from 1975-79. He was later elected mayor of Anchorage from 1981-87, the NGA says.

In 1994, he was elected governor in large part because of an endorsement by the Alaska Federation of Natives, representing the regional and village native corporations, said Carl Shepro, associate professor of political science at the University of Alaska, Anchorage.

Along with working on Alaska native subsistence rights, Knowles initiated the "Smart Start" program to ensure health care for all children, and a "Quality Schools" program that incorporated mandatory standards, comprehensive testing and remedial action with increased funding, according to the NGA.

He sued the Environmental Protection Agency over air quality mechanisms when the federal agency stopped construction of a new generator at the Red Dog zinc mine in Northwest Alaska. He also sued the Clinton administration over a rule that would block most road construction, logging and mining in unroaded parts of national forests.

Knowles also has been a strong proponent for opening the coastal plain of the Arctic National Wildlife Refuge to drilling, lobbying Congress and those within his party to allow the activity to proceed.

Knowles' two terms as governor ended in 2002, but he has used his pro-business, pro-growth record to argue for his election to the U.S. Senate.

A 30-second campaign ad, featuring former Alaska Labor Commissioner Ed Flanagan, praises the former governor for his work to increase jobs and support families and for "standing up" to both the federal government regarding his lawsuits and to "his own party to fight to open ANWR."

Other campaign ads in which Knowles and Murkowski fire shots at each other emphasize the closeness of the race.

A radio spot from Murkowski released in September criticizes Knowles for endorsing a Pew Oceans Commission report that suggests scaling back on regional authority over commercial ocean fishing in favor of a new federal agency and conservation measures. Murkowski said the report's recommendations would harm Alaska's fishing industry.

The Knowles campaign said the former governor participated in the bipartisan panel to voice Alaska's interests, and that he supports the report's push for more ocean habitat protections, according to the Anchorage Daily News.

Knowles, in turn, issued a statement condemning a federal effort to expand fish farms in the United States and saying Murkowski should be doing more to stop the proposal, the newspaper reported.

-- Compiled for the Online NewsHour by Larisa Epatko