Like many of her generation, Teresa left Ireland for America in September 1895. She settled first in Boston, and later moved to New York. While there she met and later married Richard Brayton, a French Canadian who worked in the Municipal Revenue Department. She became interested in politics while in America, and was an active supporter of the Irish Republican Brotherhood. Teresa is generally remembered as a folk poet of Irish America. As an activist Teresa organized fundraisers and distributed political pamphlets. She returned to Ireland on a number of occasions, and was acquainted with many of the leaders of the 1916 Rising.
Her writing career began when she got some assignments for Irish-American newspapers. Teresa began to write poetry for such papers as the Irish World ,New York, The San Francisco Monitor and many other publications. The pain of being separated from her native country is one of the themes of her work. In one of her poems In Cappagh Hill she describes how she dreamed of being back in Cappagh, but was shocked to awake to find she was on Broadway in New York. Teresa’s great-grandfather had taken part in the Battle of Prosperous during the 1798 Rebellion, and she wrote poems for the centenary of the rebellion in 1898.Always aware of the political climate back home, and the struggles of the Land League and the National League she campaigned for both. Teresa wrote nationalist poems on their behalf for local newspapers such as the Nation and the Westmeath Independent.
Her poem, The Old Bog Road became famous as the song of the Irish exile, and was set to music by Madeline King (later O’Farrelly), a native of Rochfordbridge, Co. Westmeath. Teresa has been compared to the Meath poet Francis Ledwidge. She is regarded as an important folk poet of the Irish-American, who readily identified with her work, especially her poems of exile. The poem Rosse’s Homecoming is considered to be one of her most political. This poem is about the return of the body of Jeremiah O’Donovan Rossa a Fenian. In recognition of her efforts Countess Markiewicz gave her a splinter from the flagpole that flew over the G.P.O. during the 1916 rising “as a tribute to your beautiful verses that are an inspiration to lovers of freedom and justice.”
Teresa returned permanently to Ireland in 1932 aged sixty-four. She settled first in Bray, Co. Wicklow, and later on the North Strand Dublin where she witnessed the bombing on 31 May 1941 during World War II. The last three years of her life were spent at Kilbrook where she died on the 19 August 1943. She was buried in the nearby Cloncurry cemetery. Enfield Muintir Na Tire erected a Celtic cross over her grave. President Eamon De Valera performed the unveiling ceremony on 18 October 1957. In his oration he spoke of the importance of Teresa Brayton as a revolutionary poet. Many of her memorabilia are displayed in the Teresa Brayton Memorial Library in Kilcock.