She was born in Lima, Ohio as Susan Weisenbarger and raised Presbyterian. She graduated from Denison University and holds a Master's degree from Sarah Lawrence College. Prior to becoming a Congresswoman, Kelly held jobs as a small business owner, patient advocate, rape counselor, and educator. She is married to Edward Kelly, and they live in Katonah, New York. They have 4 children and 8 grandchildren.
When Congressman Hamilton Fish, Jr., a Republican, decided not to seek re-election in 1994, Kelly sought and won the nomination for the congressional seat. Kelly defeated Fish's son, Hamilton Fish V, who ran as a Democrat, and Conservative Party candidate, former congressman Joseph DioGuardi, who had been defeated by her in the Republican primary but continued campaigning. In 2004, Kelly easily won re-election with 67% of the vote in New York's 19th Congressional district although the New York Times described Kelly's opponents in previous races as "token opposition".
Kelly highlighted her socially moderate and fiscally conservative voting record. A 2007 survey of congressional power and effectiveness by the nonpartisan Knowlegis company showed that Rep. Kelly was among the 100 most powerful lawmakers in the 435-member House. The survey also labelled Kelly as the second most powerful congressperson in the New York delegation, second only to Thomas M. Reynolds, who was chairman of the National Republican Congressional Committee.
On November 7, 2006, Kelly was narrowly defeated by Democratic opponent John Hall by less than 4700 votes. On November 16, nine days after the election, she conceded the election. The state certified the official voting results on December 15, 2006. It is notable that although Hall barely outperformed Kelly's previous Democratic challengers in 2004, 2002, and 2000, Kelly herself received over 80,000 fewer votes than she had in 2004.
Initially, Hall's candidacy was considered a "long-shot," but he gained momentum after Kelly faced criticism in October 2006 for her connection to the Mark Foley scandal. Kelly refused to speak to a reporter from a local news network about the matter and also did not appear at a televised debate sponsored by the League of Women Voters. Kelly was represented by an empty chair at the debate.
Kelly was endorsed by the League of Conservation Voters, an environmental advocacy group. Her score of 92% was the highest among any Republican Member of Congress in 2006. Kelly had earned a 17% score from the LCV in 2005, but attributed that score to the many missed votes that came in the several days she was absent due to a death in the family.
Kelly stated she was an "independent voice" in Congress, but the Times Herald Record noted that in 25 of the closest House votes during her last session, Kelly sided with the Republican leadership 24 of those times.
In 2006, comedian Stephen Colbert invited Kelly to an interview for his "Better Know A District" segment on The Colbert Report. Upon Kelly's refusal, Colbert interviewed Kelly's challenger, John Hall. Colbert took credit for Hall's election win on this November 8, 2006 edition of the Colbert Report.
Kelly is a member of The Republican Majority For Choice, Republicans for Choice, The Wish List, The Republican Main Street Partnership and Republicans for Environmental Protection. She received a score of average score of 30% from NARAL from 1994 to 2005, and an average of 71% from 2000–2005. Her Sierra Club rating of 63% was 8th highest among Republicans during her congressional career, and 159th overall in the House. Some seniors advocacy groups have questioned her votes on Social Security and Medicare. The Sierra Club chose to endorse her competitor in 2006. She has a lifetime rating of 64% from the American Conservative Union demonstrating a moderate to conservative voting record.
Kelly, a former small business owner, received a 22% rating from the US Women's Chamber of Commerce. She received a grade of a C+ from the Iraq and Afghanistan Veterans of America, an issue which she felt strongly on because of her nephew's service in Iraq and Afghanistan with the United States Special Forces. Kelly voted in favor of so-called "pork amendments 84% of the time according to the conservative Club for Growth, and has declined to answer questions from the National Taxpayers Union, a non-partisan group focused on taxpayer's waste.
In February 2006, the House voted 216 to 214 to cut domestic spending by $39 billion, primarily by cutting $11 billion from Medicaid and another $12.7 billion from federal student loans, which led to minor protests in her district. Sue Kelly and Frank LoBiondo (NJ-02) were the deciding votes.
She voted for the Federal Marriage Amendment to permanently ban gay marriage in all states once in 2004 and again in 2006. These votes cost her the endorsement of the Human Rights Campaign, which had supported her campaigns prior to 2004. Her rating on the Human Rights Campaign Congressional Scorecard is 25%.