Throughout her life Arnstein worked for the United States public health sector and several American colleges, eventually becoming dean of the Yale School of Nursing in 1967.

Arnstein also participated in Congress discussions in relation to provisions given to the health sector by the state through the Second Supplemental Appropriation Bill of 1957.

Through this time Arnstein was eventually promoted to supervisor but soon left to complete studies in order to become a public health nurse.

After working for the public sector for three years she accepted a job offer from the University of Minnesota to develop their nursing program.

[5]   As Arnstein's role for the UN finished up she moved to Washington, D.C., after being offered the position as assistant to the chief of the Bureau of Medical Services’ Nursing Division.

In September 1960, Arnstein was appointed the inaugural Chief of the new division[9] and held the position until 1964 when she moved to the Office of International Health.

From 1964 to 1966 Arnstein worked on seven different Rockefeller research projects with involvement in Ethiopia, Guatemala, Hawaii, Jamaica, Thailand and two joint investigations in Senegal/Nigeria and Nairobi/Sudan.

[10] Arnstein ended her public health career in 1966 and began teaching as a professor at the University of Michigan from October 1966 until August 19, 1967,[11] when she moved and became the Dean of Nursing at Yale later that year.