When he was 21, Johann decided to become a monk and dedicate his life to religious contemplation and scientific research. Like many young men of his time, Johann (now Gregor) found security and happiness in the life of a monastery. Four years later, he was ordained a priest. He attended the University of Vienna to study science and mathematics before returning to the monastery. His duties at first included ministering to dying people in the hospital, but this was so stressful for Gregor that his superiors assigned him to teaching and research.

He took a leave of absence in 1851 to attend the University of Vienna, where he wanted to study to become a teacher.  However, he apparently flunked the elementary teacher's examination. But he returned to the monastery and became a teacher anyway, teaching math and natural science.

As a teacher, Gregor became an immediate success and was very popular with both staff and students. As a researcher, Gregor puttered around in a garden, and as we will see, Gregor more or less invented the science of genetics.

But Gregor's goal was not to found genetics. In college, his botany teachers impressed him with Darwin's recently announced theory of evolution. This set Gregor to thinking more deeply about how things worked in the selective breeding of plants and animals that was practiced by farmers in his home village and throughout the region. In particular, he wanted to know more about if and how new species might be created from mating parents of different characteristics. He never created any new species, but he did create many different strains of the same species by cross breeding various kinds of peas in his monastery garden.