Harang graduated from Patrick Henry High School then went on to San Diego State University. He was first drafted by the Boston Red Sox in the 22nd round of the 1996 amateur draft, but did not sign with the team. After college, he was drafted by the Texas Rangers in 6th round of the 1999 draft and signed with them. In 2000, he was traded with minor leaguer Randy Cullen to the Oakland Athletics for Randy Velarde. He played sparingly with the Athletics, appearing in 23 games in 2002 and 2003, mostly as a starter. During the 2003 season, he was traded to the Reds along with Joe Valentine and minor leaguer Jeff Bruksch for José Guillén.