Templeton attended Union College in Schenectady, New York from which he graduated in 1980 with a BSc in electrical engineering. After graduation, he immediately joined Texas Instruments (TI) where he held a variety of positions. In May 2004, Templeton was named CEO and, in April 2008, succeeded Tom Engibous as chairman of the Texas instruments board. Templeton led TI's United Way campaign and has also chaired the Metropolitan Dallas United Way campaign. In 2012, he received the Robert N. Noyce Award from SIA for contributions to technology or public policy. During a 2015 speaker series, Templeton discussed his workplace mandate to create an environment where employees feel engaged in work and participate in community projects. In 2018, Templeton resigned as CEO, though soon resumed the role when his successor resigned, remaining chair throughout the transitions.