Profiles of the new senators elected Tuesday:
ARKANSAS: Republican Tom Cotton
The congressman, a Harvard Law School graduate and Army veteran, unseated Democrat Mark Pryor.
Cotton, 37, says he was inspired by the Sept. 11 attacks to join the Army. He worked as a clerk on a federal appeals court and briefly in private practice before enlisting. He served nearly five years on active duty, including two tours in Iraq and Afghanistan. He worked for McKinsey and Co. as a management consultant after leaving active duty.
He won a House seat from south Arkansas in 2012, and has drawn support from groups such as the conservative Club for Growth.
Cotton and his wife, Anna, are expecting their first child in April.
COLORADO: Republican Cory Gardner
Also a GOP congressman, Gardner is a fifth-generation Coloradan and son of a tractor salesman. He lives in the small northeastern agricultural town of Yuma, near the Nebraska border, in a house where his grandparents lived.
After graduating law school at Colorado State University, Gardner worked for Sen. Wayne Allard, R-Colo., before being appointed to fill a vacancy in the state House in 2005. He won the seat in 2006.
In 2010, he defeated Democratic U.S. Rep. Betsy Markey in a district that includes his hometown. On Tuesday, he sidelined Sen. Mark Udall.
Gardner, 40, shook up the Senate race with a last-minute entry in February. His campaign emphasized his youth and upbeat demeanor, calling him "a different kind of Republican," although he has a traditionally conservative voting record.
Gardner opposes abortion rights but fended off Democratic attacks over his possible support for measures limiting contraception by pushing a plan to allow the purchase of birth-control pills over the counter.
Gardner also tacked to the center on immigration, hinting he could be open to allowing people in the country illegally to remain in the U.S.
Gardner is married with two children. He and his wife, Jaime, are expecting their third child.
GEORGIA: Republican David Perdue
The first-time candidate is former CEO of Reebok, Dollar General and the failed North Carolina textile firm of Pillowtex. Perdue, 64, is the cousin of former Georgia Gov. Sonny Perdue, but he won a crowded primary by running as an outsider and defeating three congressmen.
Perdue says he opposes the Senate's immigration bill and a minimum wage increase, and he wants to repeal the president's health law. He argues also for a tax overhaul that would allow multinational corporations to move foreign cash back into their U.S. operations without taxation.
Perdue's emphasis on his business career left him on the defensive much of the fall, as Democrat Michelle Nunn framed him as a greedy executive who mistreated workers. She cited a Dollar General settlement with about 2,000 female employees who alleged gender-pay discrimination and a deposition in which Perdue said he "spent most of my career" outsourcing.
IOWA: Republican Joni Ernst
Ernst was a relatively unknown state lawmaker and lieutenant colonel in the Iowa National Guard when she entered the competitive primary over a year ago. But that all changed with a catchy television ad in which she promoted her experience castrating hogs on the family farm and pledged to cut pork and "make 'em squeal" in Washington.
The 44-year-old won a close race against Democratic Rep. Bruce Braley. She pitched herself as a "mother, soldier and independent leader."
Ernst attended Iowa State and often says that her time on an agricultural exchange program to the Soviet Union made her want to serve in the federal government.
As a colonel commanding a transportation company, she led daily convoys of 60 trucks from Kuwait into Iraq in 2003 and 2004. She returned to hold county office and won a state Senate seat in 2010.
Ernst lives in Red Oak with her husband Gail Ernst, who is retired from the military, and their daughter Libby. She also has two adult step-daughters.
MICHIGAN: Democrat Gary Peters
Peters, a three-term House member, beat Terri Lynn Land, a former Michigan secretary of state, to succeed retiring Democratic Sen. Carl Levin.
In the House, one focus for Peters has been the auto industry. He supported the federal bailout and government-led bankruptcy reorganization of General Motors and Chrysler and has served as co-chairman of the bipartisan House Automotive Caucus.
Peters, 55, served on the city council in Rochester Hills in the early 1990s before moving on to the Legislature.
He is married with three children and lives in the Detroit suburb of Bloomfield Township. He has also been a professor, financial adviser, lieutenant commander in the Naval Reserve and state lottery commissioner.
MONTANA: Republican Steve Daines
Daines, 52, spent decades in the private sector before entering politics. He began honing his rhetorical style in high school in Bozeman as the debate partner of Mike McFaul, ambassador to Russia under President Barack Obama.
After earning a chemical engineering degree from Montana State, Daines went to work for Procter and Gamble, eventually moving with his wife, Cindy, to China when the company began expanding its business in Asia. They spent five years there before Daines returned home to work for his father's construction business.
He later joined a high-tech startup that has since been sold to Oracle Inc.
Daines was the nominee for lieutenant governor in 2008 but lost. He won an open seat for Congress in 2012 and jumped into the Senate race when Democrat Max Baucus .
Less than a year after that victory, Daines launched his run for Senate after longtime Democratic Sen. Max Baucus was named ambassador to China.
On Tuesday, Daines easily defeated state legislator Amanda Curtis, who became the Democratic nominee after Baucus' appointed replacement, John Walsh, abandoned the race following a plagiarism scandal.
NEBRASKA: Republican Ben Sasse
The 42-year-old president at Midland University attracted national tea party support despite an establishment resume and years spent in Washington.
Sasse served as an assistant secretary of health and human services under President George W. Bush. He was educated at Harvard, Oxford University and St. John's before getting his Ph.D. in American political history, strategy and management from Yale.
He told voters that he understood the federal health care law in depth and could offer workable alternatives. Aided by endorsements from Sen. Ted Cruz of Texas and former Alaska Gov. Sarah Palin, Sasse carried nearly half of the Republican vote and all but one of Nebraska's 93 counties in a crowded primary.
Sasse was born in Plainview and grew up in Fremont. He was 37 when he was named in 2009 to lead what was then Midland Lutheran College in Fremont, making him among the youngest college presidents in the country. Since then, enrollment has soared from less than 600 to more than 1,000. Sasse also oversaw the rebranding of the school as Midland University, which included the addition of new athletic programs.
Sasse and his wife, Melissa, live in Fremont with their three children. He defeated Democrat Dave Domina, an Omaha lawyer.
NORTH CAROLINA: Republican Thom Tillis
The state House speaker, a former IBM consultant, campaigned on how he helped bring to power GOP state legislators who reduced taxes and regulations and reined in spending.
He toppled Democratic Sen. Kay Hagan in the most expensive Senate campaign in the nation.
Tillis, 54, was born in Jacksonville, Florida, one of six children in a family that moved often through the South.
After high school, "I was working in a warehouse and I was living in a trailer park," Tillis said this year. "And it never occurred to me that government was going to solve my problem."
By age 25, Tillis and his high school sweetheart had divorced. But his business career began progressing. Work ultimately moved him to North Carolina in the late 1990s, where he settled north of Charlotte. Remarried and with two children, Tillis got his college degree at age 37.
Tillis entered politics as a town commissioner and was elected to the state House in 2006. Two years later he became minority whip and later quit IBM job to focus on electing a GOP majority in 2010. Colleagues rewarded him with the speaker's post.
While viewed as part of the GOP's moderate business wing, Tillis helped lead a Legislature that approved private school vouchers, further restricted abortion and put on the ballot a proposed constitutional amendment to ban gay marriage, which voters passed in 2012.
OKLAHOMA: Republican James Lankford
The two-term congressman from the Oklahoma City suburb of Edmond is a Baptist minister who rose quickly among the leadership ranks in the House.
The 46-year-old Lankford won the GOP nomination in June over a seven-man field that included a politically connected state legislator in T.W. Shannon, a former speaker of the state House who had endorsements from tea party favorites.
In a solidly Republican state, Lankford's primary victory was his greatest hurdle. His campaign got a boost when retiring GOP Sen. Tom Coburn, Lankford's successor, denounced negative ads in the race in what ended up being a de facto endorsement.
Lankford was a political novice when he campaigned in 2010 for the open House seat in Oklahoma City that was being vacated by now Gov. Mary Fallin. He had the support of young evangelicals who knew Lankford from his 13 years as director one of the largest Christian youth camps in the country.
His grasp of GOP positions helped land him a leadership position as chairman of the House Republican Policy Committee.
SOUTH DAKOTA: Republican Mike Rounds
The insurance and real estate executive spent 10 years in the state Senate before running for governor in 2002. In the primary, two other candidates traded shots in attack ads, while Rounds — the self-proclaimed "guy behind door No. 3" — won over voters with a positive message.
He was governor for two terms. Now he will be a senator after beating Democrat Rick Weiland and independent candidates Larry Pressler and Gordon Howie.
Rounds, 60, has said he wants to start work on the Keystone XL pipeline, help repeal the health care law and enact an immigration overhaul.
Rounds led most of the campaign, but criticism over his involvement with a visa program aimed at spurring foreign investment in South Dakota led to an influx of national money and made the race briefly competitive.
He and his wife, Jean, have four children and six grandchildren.
WEST VIRGINIA: Republican Shelly Moore Capito
The congresswoman will be the first female senator from West Virginia. She is also breaking a five-and-a-half-decade streak of only Democrats representing the state in the Senate.
Capito, 60, is succeeding retiring Democrat Jay Rockefeller after beating Natalie Tennant, West Virginia's secretary of state.
In the House, Capito has represented some of the state's most populated regions, including the capital of Charleston and the growing Eastern Panhandle. She was first elected to the House in 2000, and was a state lawmaker before that.
Her father, Arch Moore, spent 12 years and three terms as Republican governor in the late 1960s, 1970s and 1980s.
Capito has been a staunch critic of the president's energy policies. The administration's push to limit carbon emissions from coal-fired power plants faces plenty of opposition in West Virginia, where the state's southern coalfields are already struggling.
Capito also has voted to repeal the health law.
She has a bachelor's degree in zoology from Duke University and a master's degree in education from the University of Virginia.
She and her husband, Charles Capito, have three children.