During her life she was also noted as a one-time owner and operator of Los Angeles-based Gilpin Airlines, a speaker at the 1932 Democratic National Convention, and a bridesmaid at the wedding of Eleanor and Franklin D.

Her father Tilden Selmes was a Yale-educated attorney who originally practiced in St. Paul where he met her mother.

Tilden continued to practice law, and was for a time an associate counsel for the Northern Pacific Railroad.

She became friends with Eleanor Roosevelt's cousin, Corinne Robinsion, who would read a Jack London book to Isabella as they drove to balls to make sure they remembered the world's problems.

[8][4] This would have been especially difficult, as at the time, tuberculosis patients were told to have their own utensils and bedding and avoid touching others.

[8] In 1923, Isabella married a close friend, Gen. John Campbell Greenway (1872–1926), another of Roosevelt's Rough Riders, whom she had met in 1911.

Isabella continued to write to Greenway, with her husband's knowledge, through his service in Europe during World War I.

She successfully campaigned for a Statue of John Campbell Greenway to be placed in the United States Capitol Building and facilitated its creation.

[12] Isabella and her children moved to Williams, Arizona, and bought the Quarter Circle Double X Ranch as she and John had planned.

[8] In 1927, Greenway opened Arizona Hut, a furniture factory employing disabled veterans and their immediate families.

He had been asked to run for governor and received a nomination for vice president at the 1924 Democratic National Convention.

[4] Although Smith lost, Governor George W. P. Hunt said of Greenway ""No other woman in Arizona did as much for the success of the party.

[16]In 1932, Greenway campaigned heavily for Franklin Roosevelt and was credited with assuring his support from Arizona.

[17] When the nomination process stalled at the end of the third ballot, Greenway convinced the California delegation to meet with Roosevelt's campaign director, Jim Farley.

[18] Greenway continued to campaign for Roosevelt in Arizona, even hosting him at her ranch during his tour of western states.

Greenway's platform included support of a copper tariff, farm relief (though she called it "agricultural equality"), and countering anti-female bias.

She also continued to work to revive Arizona's copper mining industry and support veteran's benefits.

Her campaign faced controversy when $4 million earmarked for the Verde River Irrigation Project was rescinded, leading homesteaders to hang and burn effigies of Greenway, Harold L. Ickes, and Benjamin Baker Moeur.

She also opposed some provisions of the 1935 Social Security Act, which she believed would be impossible to implement in the long term.

[19] She claimed that Arizona was in a better situation, as the mines and farms were improving, and noting she wanted to spend more time with family.

Her son Jack later explained that her retirement was due to her being worn out from being Arizona's sole representative.

After her retirement, King divorced his wife of twenty-two years and began courting Greenway.

[8] In response to her disloyalty, Roosevelt invited Greenway's children, without their mother, to dinner at the White House.

She was elected to chair the American Women's Voluntary Services and the Arizona Inn was deemed essential to the war efforts in order to provide accommodations near the local air base and naval training schools.

[23] In 1981, Greenway was posthumously inducted into the Arizona Women's Hall of Fame as a member of the inaugural cohort.