Nicknamed Arte by family and friends, Moreno is a native of Tucson. From 1966 to 1968, he served with the Army, fighting in the Vietnam War.
In 1973, he graduated from the University of Arizona, with a degree in marketing. That same year, he was hired to work at a company named Eller Outdoor.
He would travel across the country for the next seven years, Eller Outdoor moving him around several times. However, in 1984, he moved back to Arizona, settling in Phoenix. He was hired by Outdoor Systems there. It was while at Outdoor Systems that he was first able to make his mark as a businessman: Under his leadership, the company's total profits grew from 500,000 dollars to 90 million dollars in less than ten years. Being that baseball is his favorite past-time, he bought the minor league team Salt Lake City Trappers alongside 17 other investors, and married his girlfriend Carole in 1986.
In 1996, Outdoor Systems went public, and in 1997, he set up the Moreno Family Foundation. In 1998, he sold Outdoor Systems for 8 billion dollars.
By 2001, Moreno was hungry to own a Major League Baseball team. He tried to buy a controlling part of his hometown's Arizona Diamondbacks, however, no deal could be reached. He insisted on trying to buy a major league team and set his sights on the 2002 World Series champions Anaheim Angels. On April of 2003, it was announced he had reached a deal with The Walt Disney Company, to obtain the team for 180 million dollars. And, in a historic meeting on May 15 of that year, MLB commissioner Bud Selig announced the sale of the Angels to Moreno had been approved.
One of the first people to congratulate Moreno after the news was Diamondbacks' owner Jerry Colangelo, a personal friend. Colangelo declared that it was a good opportunity for Moreno.