McLachlin was born in Honolulu, Hawaii. He graduated from Punahou School in 1997 and UCLA in 2002 with a degree in sociology.
McLachlin turned professional in 2003 and played on mini-tours until 2006 when he played the Nationwide Tour. He played on the PGA Tour in both 2007 and 2008 after successfully completing qualifying school each year. In 2008, he won his first PGA Tour event, the Legends Reno-Tahoe Open, and secured his tour card through 2010. McLachlin has not played full-time since 2010.