Schierholtz was a second-round draft pick by the Giants out of Chabot College in 2003. He reached the major leagues in 2007, batting over .300 in limited playing time. He spent most of 2008 in the minor leagues but again hit over .300 when he was called up in September. Schierholtz also represented the United States of America at the Summer Olympics that year. In 2009, he spent the whole season with the Giants, appearing in over 100 games and getting starts in right field. Schierholtz was the Giants' starting right fielder for portions of 2010 but ended the year as a defensive substitution for Pat Burrell. He won his first World Series as the Giants defeated the Texas Rangers for their first World Series title in 56 years. In 2011, he was the Giants' starting right fielder for most of the year, until a broken foot sidelined him at the end of August. Though used as the starting right fielder some in 2012, Schierholtz said in an interview in July that Giants' manager Bruce Bochy did not think of him as an everyday player. Shortly afterwards, he was traded to the Phillies, with whom he finished the year. The Giants won the World Series again and gave him a World Series ring for his earlier contributions.