Haddock achieved national fame when, between the ages of 88 and 90, starting on January 1, 1999, and culminating on February 29, 2000, she walked over 3,200 miles (5,100 km) across the continental United States to advocate for campaign finance reform.

On August 19, 2004, Haddock's request was officially granted by Judge John Maher during a hearing at the Cheshire County probate court.

[3] After marrying, she started a family; she had a daughter, Betty and a son, James Jr.. She worked during the Great Depression and was employed for twenty years as an executive secretary in the offices of the BeeBee Shoe factory in Manchester, New Hampshire.

She also had 16 great-grandchildren:[4] Kyle, David, Jennie, Kendall, Peyton, Matthew, Richard, Grace, Justin, William, James, Beatrix, Tucker, Mathilda, Parker, and Clay.

[citation needed] Haddock celebrated her 100th birthday on January 24, 2010,[5] and died six weeks later on March 9, 2010, at her son's home in Dublin, New Hampshire, following a bout with respiratory illness.

[6] In 1960, Haddock began her political activism when she and her husband successfully campaigned against planned hydrogen bomb nuclear testing in Alaska that threatened an Inuit fishing village at Point Hope.

When Granny D arrived in Washington, D.C., she was 90 years old (having begun the journey at 88 and having two birthdays en route), had traveled more than 3,200 miles, and was greeted in the capital by a crowd of 2,200 people.

A film, "Granny D Goes to Washington," by Alidra Solday, documents her walk across America, and was broadcast on PBS stations nationwide, 2006-2008.

[7] Haddock worked closely with state representative Betty Hall, another New Hampshire grandmother, on campaign finance reform.

[9] She entered a plea of guilty, then made a statement to the court reiterating "campaign finance reform" as the purpose of their demonstration.

True to her "clean elections" ideals, Haddock funded her late-entry campaign by accepting only modest private-citizen donations.

Granny D continued to be active in politics to the end of her life, and celebrated her 98th, 99th and 100th birthdays by lobbying for campaign finance reform at the New Hampshire State House.