Due to redistricting, Napolitano ran for and won reelection in the 2012 United States elections in California's 32nd congressional district against Republican nominee David Miller.

After high school, she married Federico "Fred" Musquiz and moved with her husband to Norwalk, California, where they raised five children.

[3] Napolitano began her political career as a member of the Norwalk City Council, winning her first election in 1986 by 28 votes.

During her council tenure, she focused much of her attention on providing access to constituents and on redevelopment and transportation issues to address the city's need for jobs and a more diversified economic base.

[5] Three days before the candidate filing deadline, U.S. Representative Esteban Torres announced his retirement, hoping the late timing of his decision would help his son-in-law, James "Jamie" Casso, win the seat.

[6] A 2009 story first reported by Bloomberg News[7] and further detailed by the Los Angeles Times[8] questioned the personal loan interest rate that the Federal Election Commission authorized Napolitano to use during her 1998 campaign for Congress.

[11] In 2011, Napolitano voted against the National Defense Authorization Act for Fiscal Year 2012 as part of a controversial provision that allows the government and the military to indefinitely detain American citizens and others without trial.

At the start of the 110th Congress, Napolitano became the most senior new member of the House Committee on Transportation and Infrastructure, with jurisdiction over America's aviation system, surface transportation, freight and passenger rail, the inland waterway system, international maritime commerce, the Economic Development Administration, the U.S. Army Corps of Engineers' support of the nation's water resources, and the federal clean water program.

Napolitano's experience includes six years on the California State Assembly Transportation Committee, and current work on rail safety and congestion relief in the San Gabriel Valley.

[23] Napolitano opposed the overturning of Roe v. Wade, calling it "abhorrent" and a "dreadfully sad and dark day when you wake up with fewer and diminished rights in the United States of America.