Porter graduated from his Aunt’s elementary school in 1876. He then enrolled at the Lindsey Street High School. His aunt continued to tutor him until he was fifteen. In 1879, he started working in his uncle's drugstore and in 1881, at the age of nineteen, he was licensed as a pharmacist. At the drugstore, he also showed off his natural artistic talents by sketching the townsfolk. Porter traveled with Dr. James K. Hall to Texas in March 1882, hoping that a change of air would help relieve a persistent cough he had developed. He took up residence on the sheep ranch of Richard Hall, James' son, in La Salle County and helped out as a shepherd, ranch hand, cook, and baby-sitter. While on the ranch, he learned bits of Spanish and German from the mix of immigrant ranch hands. He also spent time reading classic literature. Porter's health did improve and he traveled with Richard to Austin in 1884, where he decided to remain and was welcomed into the home of the Harrell’s, who were friends of Richard's. Porter took a number of different jobs over the next several years, first as pharmacist then as a draftsman, bank teller, and journalist. He also began writing as a sideline.
Porter led an active social life in Austin, including membership in singing and drama groups. He was a good singer and musician. He played both the guitar and mandolin. He became a member of the "Hill City Quartet," a group of young men who sang at gatherings, and serenaded young women of the town. Porter met and began dating Athol Estes, then seventeen years old and from a wealthy family. Her mother objected to the match because Athol was ill, suffering from tuberculosis. On July 1, 1887, Porter married Athol at the home of Reverend R. K. Smoot.
The couple continued to participate in musical and theater groups, and Athol encouraged her husband to pursue his writing. Athol gave birth to a son in 1888, which died hours after birth. Then the couple had a daughter, Margaret Worth Porter, in September 1889. Porter's friend Richard Hall became Texas Land Commissioner and offered Porter a job. Porter started as a draftsman at the Texas General Land Office in 1887 at a salary of $100 a month,