Susan Collins was born in Caribou, Maine, and now lives in Bangor. She earned a bachelor's in government from St. Lawrence University in 1975.
Collins' father, Donald Collins, was a state senator, as was her late uncle, Samuel Collins, who also served on the state Supreme Court. Her mother, Pat, was a trustee to the University of Maine System.
Collins worked as an aide for Sen. William Cohen from 1975 to 1987, before serving in Gov. John McKernan's Cabinet as commissioner of professional and financial regulation from 1987 to 1992.
She was the New England administrator of the Small Business Administration from 1992 to 1993 and was deputy treasurer of the state of Massachusetts for eight months in 1993.
Collins was elected to the U.S. Senate in 1996.
She is married to Thomas Daffron, a longtime consultant to Maine congressional candidates who hired Collins for Cohen's congressional office in 1974.
Susan Collins, a Republican, burst into national media reports in early 2009 when she voted with Democrats to approve the approximately $800 billion economic stimulus package backed by President Barack Obama.
Collins' vote and that of two other Republicans were crucial in passing the stimulus. Her vote polished her image as a moderate and won her praise for her independence.
In August 2010, Collins and fellow Maine Republican Sen. Olympia Snowe threw their support behind Obama Supreme Court nominee Elena Kagan, and both voted for a $26 billion Medicaid funding and education bill. Their stands on both countered the GOP line but won them praise from within Maine.
But Collins' moderate stance has since been tempered by her opposition to the 2010 health care reform bill.
In July 2012, Collins cast her 5,000th consecutive vote, dating back to January 1997.
With Snowe's decision not to seek re-election in 2012, Collins is destined to become Maine's senior senator.
Collins has secured committee posts that have heightened her profile in homeland security issues. She was appointed in 2009 to the Appropriations, Homeland Security, Armed Services and Special Aging committees. Maine has one of the nation's oldest populations.
In 2012, Collins was a leading senator in the investigation of the Secret Service prostitute scandal in Colombia.
Committee Assignments: Homeland Security and Governmental Affairs; Armed Services; Special Aging; Appropriations
American Conservative Union Rating: 55
Americans for Democratic Action Rating: 45
Susan Collins won her June 2014 primary, she will face Shenna Bellows in November.
(Last updated by The Associated Press on June 13, 2014.)