Eventually settling in Pleasant Township, Iowa, Tyrrell was soon investing in grain mills and real estate.
After learning of the 1901 Spindletop gusher in Beaumont, Texas, Tyrrell relocated his family to the area.
Tyrrell established himself in Beaumont as an oil speculator and businessman and eventually earned millions from his ventures.
An active philanthropist, he often donated to the poor, helped victims of natural disasters, and otherwise performed numerous other generous deeds throughout his lifetime.
As an investor during economically depressed times, Tyrrell provided much-needed capital to fledgling entrepreneurs and struggling businesses, such as funding the development of the city's first commercial port, contributing to an irrigation system to support the area's growing rice culture, and investing heavily in residential and commercial development.