Born in the farming community of Polk, Missouri, Mary Allen was the daughter of a minister and farmer, Rev. J.C. Allen. After marrying George W. Wright, the couple moved west to Rockford, Washington and then to Rathdrum, Idaho in 1890. During this time, Mary worked as a teacher and became active in the populist movement and woman's suffrage.

In 1898, Mary Allen was nominated for State School Superintendent of Public Instruction by the Populist Party. She declined that nomination, and instead ran for and was elected to the Idaho State Legislature. Representative Wright served as the Chair of the Populist Caucus in the fifth session of the Idaho House of Representatives, becoming the first woman to lead a party in a state legislature. After completing her term, she was elected Clerk of the House for the sixth session in 1901, and convened the seventh session in 1903. She was additionally elected delegate to the national convention in Sioux Falls, South Dakota, and continued to work professionally in politics until the Populist Party ceased to exist. After serving as Secretary of the Idaho Pan American Exposition Committee in late spring 1901, Mary worked for Congressman Thomas L. Glenn until she sued him in court for unpaid wages.

In 1904, Mary Allen divorced her husband and returned to teaching in Northern Idaho. She also studied law and managed Wright's Loan and Investment Company in Bonners Ferry.