The Peter Henry Rolfs Digital Collection contains Rolfs' publications and unpublished papers, some written in collaboration with Clarissa Rolfs. Also included are photographs taken by the Rolfs, correspondence with Professor Rolfs and Clarissa Rolfs, and administrative reports written by Rolfs during his years in Brazil. For more information, see the collection Finding Aid.

Rolfs worked from 1892-1899 at the Agricultural Experiment Station at the Florida Agricultural College in Lake City as a researcher and instructor in Botany and Horticulture. From 1899-1901, he served as a botanist and bacteriologist at the Clemson Agricultural College and Experiment Station. He returned to Florida in 1901 as head of the USDA's Plant Introduction Station and Subtropical Laboratory in Miami. From 1906-1921, he served as the Director of the Florida Agricultural Experiment Station. He also was Director of Agricultural Extension in Florida, 1915-1920, and Dean of the College of Agriculture, 1915-1920.

In 1920, Rolfs accepted an invitation to establish and direct an agricultural school in the Brazilian state of Minas Gerais. Rolfs served as Director of the Escola Superior de Agricultura e Veterinaria do Estado de Minas Gerais, em Viscosa, until 1929, when he became a technical consultant on agricultural affairs for Minas Gerais. He retired in 1932. During his stay in Brazil, Rolfs was assisted by his daughter, Clarissa, who functioned as his personal secretary, translator, and advisor. After 1932, Professor Rolfs and Clarissa traveled throughout Brazil, South America, and the U.S. studying agricultural education.