Pippin had completed three tours of duty with the Marines in Iraq and was about to be deployed to Afghanistan with the California National Guard when he disappeared. After visiting family in his home state of Michigan, Pippin left on August 25, 2010 to prepare for his deployment. He stayed at the Hungry Horse Hotel in Flathead Valley, ordered a pizza and dropped his rental car off at the Glacier Park International Airport. He was supposed to show up in San Diego, California for his California National Guard drill on September 10, but never arrived.

Three hunters encountered Pippin hiking on a trail near My Lake on September 14, four days after he didn't appear for drill. He appeared to be in good health. The hunters gave him some bottles of water and then they parted ways. Some Forest Service rangers also saw Pippin sleeping on the trail around that time period and spoke to him briefly. A family who was camping in the area at that time said they saw Pippin as well in an area called Chinese Wall, near Salt Mountain. They offered to let him camp with them but he declined. He said he planned to continue to follow Chinese Wall South. This is the last known sighting of him.

Pippin played football in high school. He enrolled in Central Michigan University, then transferred to Michigan State University after two years. He changed majors twice, from journalism to philosophy and then to pre-law, and eventually left college without a degree and joined the Marine Corps in 2003. He was honorably discharged in 2007 and worked for three years as an officer with the Los Angeles Police Department in California. He lived out of his car for months following his discharge, because he didn't have enough money to find an apartment. He enlisted in the California National Guard for financial reasons; they provided a $20,000 sign-up bonus. Pippin had few possessions, did not date and had never had a serious romantic relationship. He didn't form any close friendships with the police department and failed to keep in touch with his Marine Corps friends after he was discharged, although some of them lived in the local area. He spent his free time working out, playing video games and reading.

In 2010, Pippin got notice of his pending deployment with the National Guard. He abruptly quit his job with the police department and gave away all his belongings, telling his family he planned to live out of his car until he was deployed. He left his expensive watch behind with his family before he went to Montana, and told his parents to give it to his brother. He also gave his mother his Kindle electronic reader, saying he didn't need it anymore, and canceled his accounts on several websites. Pippin's parents stated he seemed troubled at the time of his disappearance, although not necessarily depressed. He was never diagnosed with post-traumatic stress disorder, but he did show some of the symptoms after his experiences in Iraq.

The circumstances of Pippin's disappearance are unclear. His family stated his disappearance is completely out of character and it's unlike him to shirk his military duty. There are indications that he may still be alive; someone had been using his credit card, and paying off the purchases, as recently as March 2011. His case remains unsolved.