Helen served three terms in the Texas House of Representatives:
- 41st Legislature: January 1929 - March 1930
- 42nd Legislature: January 1931 - November 1932
- 44th Legislature: January 1935 - October 1936
In her first term, she joined Laura Burleson Negley of San Antonio as the only women in the House.
During her legislative service, Helen remained a firm proponent of states' rights. She also worked to better living conditions in her home district by sponsoring legislation to give the City of Texas City ownership of the Texas City Dike, so beach areas could be better patrolled. She sponsored a bill which opened East Galveston Bay part of the year to commercial fishing, which won her grateful support among those who fished for a living.
Helen's legislative record also reflects her strong support of the medical profession. She helped defeat bills exempting chiropractors from the requirements to meet the same standards as doctors, and was very active in issues regarding medical schools and medical training.
Holman Taylor, secretary of the Texas State Medical Association, praises Helen in a letter supporting her for a second term,
We have found her ready to listen to our legislative requests, and her vote has always been for those measures which have given the greatest promise for public good on sound economic and scientific bases. We look upon her as one of the strongest and most constructive legislators in our state. (Letter, 6/06/30, Helen Edmunds Moore Archives).
Helen's main concern, however, was in helping the more unfortunate citizens of Texas. In her first term she helped to pass a bill establishing schools in prisons for inmates who could not read or write. She also sponsored a resolution creating a committee to visit all state hospitals for the insane, and became a dedicated and hard-working member of that committee, making numerous visits to document overcrowding and inadequate facilities.
During her second term, to better secure additional appropriations to fix the problems she had found, Helen requested membership on the Appropriations Committee, writing in her letter of application,
I am anxious to be on the Appropriations Committee. I am sure that I can help materially toward an equitable distribution of the State's appropriations for Eleemosynary Institutions, and feel that the knowledge I have gained first hand through visiting these institutions is valuable.
Galveston Psychopathic Hospital
After gaining membership on the Appropriations Committee, she successfully obtained funding to address some of the substandard conditions in those hospitals, and was instrumental in establishing the Galveston Psychopathic Hospital.
Helen ran for a third term in the 43rd legislature but was defeated. She attributed her defeat to not having made an "active" campaign. She ran again in 1934 for the 44th Legislature (January 1935-October 1936) and was elected by a large margin. In this last term, she supported an expansion of the Galveston Psychopathic Hospital and obtained funds to increase the capacity of the Hospital for Crippled and Deformed Children, part of Sealy Hospital in Galveston. She also helped secure a change in the Texas Constitution that allowed persons to be admitted to a mental institution without being forced to endure a jury trial.
Tribute to Honorable Helen Moore
Helen was commended for her courageous fight for disadvantaged citizens by her colleagues in the legislature and the media. When she decided that her third term was to be her last, she received a Tribute to Honorable Helen Moore from the Texas House of Representatives, which declared,
…By her retirement Mrs. Moore is closing a career, which has contributed invaluable service to the eleemosynary institutions of this State and to the underprivileged of our citizenship generally, which service has not only reflected credit on the Legislature of the State of Texas, but has established Mrs. Moore as a pioneer in the humanitarian history our State… (Resolution, 10/27/36, Helen Edmunds Moore Archives).