Adrian Constantine Anson was born to Henry and Jennette Anson on April 17, 1852 in Marshalltown, Iowa, a town his father helped to found. In fact, Adrian was the first white child born in the new pioneer town and is today remembered as the “first son” of Marshalltown.

Henry Anson was born in Canadaiagua, New York but moved to Ohio with his family at the age of five. He married Jennette Rice in 1846. His pioneering spirit took him westward when, in the spring of 1851, he left Jennette and his newborn son Sturgis in Illinois while he traveled to Iowa. He found what he described as “the prettiest place in Iowa” and built a shanty on what is now Main Street in Marshalltown. With the construction of his new home completed, he returned and claimed his family. Adrian was born the following year.

Henry was a man whom wore many hats. He served as the fledgling town’s local land agent, surveyor and promoter; built the county’s first steam lumber mill; and even acted as an amateur dentist, extracting teeth with a pair of bullet molds. He also held office as the County Supervisor and was a certified Justice of the Peace. After his wife's death in 1860, he raised Sturgis and Adrian by himself.

Baseball was steadily gaining popularity as a recreational activity in the mid-nineteenth century. In 1845, Alexander Cartwright published his set of baseball rules for the Knickerbocker Club of New York. This historic publication helped to standardize the rules and field of play across the country. The National Association of Base Ball Players was organized in 1858 and the first baseball league was formed. Civil war veterans returning home often brought the game with them to places it had never been played. During the years of Anson’s childhood and early adulthood, baseball was fast becoming the national pastime.

Marshalltown grew steadily in the 1850’s and with the arrival of hundreds of settler families Adrian had plenty of peers with which to form teams and play the game of baseball. His skills on the diamond began to take shape during his teenage years and he proved a natural. Beginning in 1886, he played on the town’s second nine, a team with the name of the “Stars.” He longed to play alongside his father and brother on the first nine, and practiced year-round toward this goal, even in his father's barn during the winter months.

Young Anson was not much of a student, preferring instead the outdoors and physical activities. He often was involved in scrapes with other boys and general mischief. His father hoped to tame his wildness and so decided to send Adrian to the University of Notre Dame, which at the time accepted students as young as 14. At Notre Dame, he played in the competitive intra-school baseball league for the Juanita team with his brother Sturgis. The team competed against other student athlete squads with names such as Empire, Fashion, Star of the East, Pickwick, Quick-Step, and Young America Baseball Club. Adrian played second base, while Sturgis, the team’s star, roamed center field. He attended the university for two years before returning to Marshalltown. Back at home, Anson's bad habits soon returned. He shunned work in order to play baseball and billiards. Father Henry tried once more to send his son to school, this time choosing the State University in Iowa City. Adrian's behaviors there were scarcely better than at home, and he was asked to leave after a single semester.

After his university adventures, Adrian once again took up life in Marshalltown and returned to playing ball for the town team. He showed considerable talent with the bat and soon joined his father Henry and older brother Sturgis on the Marshalltown Base-Ball Club. With Cap at third base, Sturgis in center field, and Henry at second base, the Marshalltown team became the most prominent team in the state of Iowa and traveled as far as Omaha, Nebraska to play in tournaments.

While a member of the Marshalltown nine, Adrian took part in an exhibition game against the powerful Rockford Forest Citys of Rockford, Illinois. The Forest Citys club was a formidable powerhouse in the late 1860s. It boasted pitcher Albert Spalding and shortstop Ross Barnes, both of whom would later star for the Boston Red Stockings of the National Association. In a historically significant game held on the Fourth of July, the Forest City’s defeated the National Base Ball Club of Washington D.C., the only loss by the Nationals on their famed barnstorming national tour of 1867. During their exhibition tour of the Midwest of 1870, the Forest Citys were soundly beating town teams with scores from 30 to 100 to 1. That Marshalltown lost only 18 to 3 in their encounter was testament to the team’s sound play.

Rockford’s players and management had been greatly impressed by the play of the Anson family. It offered contracts to Henry, Sturgis and Adrian to come play for its squad. Henry wished to remain in Marshalltown and look after his business interests. Sturgis had hurt his arm playing at Notre Dame and didn't feel he had the throwing strength to play professionally. Adrian, however, jumped at the chance to get paid for playing a sport he loved. He signed his first professional contract to play for the Rockford team in 1871, the same year Spalding and Ross departed to play in Boston. It was also the first year of the newly formed, nine team National Association of Professional Base Ball Players. In retrospect, it seems poetic that Adrian C. Anson would be involved with major league baseball from day one of its existence. His first contract earned him $66.00 per month.

The Rockford Forest Citys did not enjoy much success in that inaugural year of the National Association. They finished the 1871 season with a 4-21 record, dead last among the nine teams. The Philadelphia Athletics finished first, with Chicago second and Boston third. For his part, Anson led the Forest Citys with a .325 batting average, .053 points above any other member of the team’s starting nine. In addition to batting average, he led the team in hits, total bases, on-base percentage, doubles and extra-base hits. He started all twenty-five contests, playing twenty games at third base, two at second, one at first and one in the outfield during his rookie season. That Anson could more than hold his own with the best players of the era was evident to everyone in the league. It was readily apparent to Philadelphia Athletics’ Manager Dick McBride. McBride would convince Anson to join his champions in the City of Brotherly Love for the start of the 1872 season.