Rena Green moved with her children to the Maverick Ranch in Boerne where they attended the local school. She later returned to San Antonio, where she became intensely engaged in civic activities. In 1914, she was one of the first women to serve on the San Antonio School Board. She later served on the SA Public Library Board of trustees. During WWI, as a member of the San Antonio City Committee, she successfully pushed for the hiring of the first policewomen (8 of them) and the first juvenile judge. She also opened the first legal aid office for the poor. Beyond Texas' borders, she demonstrated for women's right to vote in Washington DC. She was also a major leader in getting women's right to vote in Texas in 1918. She then worked on Texas' passage of the 19th Amendment in 1920.

     Lest one thinks this artist and mother was merely a social activist, Rena Maverick Green was passionately interested in our historic buildings. Serving as chairman of the Missions Committee of the Alamo Mission Chapter of the Daughters of the Republic of Texas, she was extremely concerned about the rapid growth of the city toward San Jose Mission. She proposed that the State purchase 1000 acres around San Jose, San Juan and Espada for a state park. She also thought restoring the acequia system would allow the property to be leased as productive farmland that "would make one of the most unique surroundings imaginable (for) the missions." She garnered the support of New York's Reginald Pelham Bolton of the American Scenic and Historic Preservation Society, Los Angeles' Charles Lummis, who had led the preservation of several California Missions, and congressman John Nance Garner.

     In early 1924, she persuaded Governor Pat Neff and the entire Texas State Parks Board to come to San Antonio to view San Jose first hand. That evening, the Alamo Mission Chapter gave a dinner at the Gunter Hotel where remarks were made by Gov. Neff, Rena Green, Clara Driscoll Sevier, the County Judge, and the San Diego, CA Chamber of Commerce VP who was in town promoting the Old Spanish Trail. His topic was "What California would do with the San Antonio Missions if they were located there."