Early on, missionary-minded relatives began to influence Miller and planted ideas of a greater goal in his mind. These relatives, including Orie O. Miller, Jay Hostetler, and Ernest E. Miller watched Miller as he grew in his faith at Forks Mennonite Church in Lagrange County, Indiana where he attended with his family. After receiving his high school degree in 1955, Miller studied for four years at Goshen College, a Mennonite school in Indiana. This continuation of his general education and Mennonite education would aid him in his Future trip. During the four years spent focusing on a Pre-Med education, Miller met his wife Mary.

Miller married Mary in 1956, just after their first year of college, creating a partnership that would allow Miller to have a greater impact on those he worked with. The wedding was a traditional Mennonite wedding where rings were absent, but the Service vows proved untraditional. Mary omitted the word "obey" from her vows, possibly accidentally. During their last three years of college, the young couple planted a church in California, Michigan, starting their focus on evangelism early on. The Miller family welcomed their first child, Shari, 18 months after the wedding. Miller began part-time jobs in order to support the family.

Miller pursued his medical degree, relocating the family and attending the Indiana University School of Medicine. He graduated from medical school in 1964 and followed with his residency in Fort Wayne, Indiana. After his residency, Miller began a family practice in Markle, Indiana. He was joined by two other physicians: Dr. Lee Kinzer and Dr. Vic Binkley. Miller is also credited with creating the first EMS Service in Bluffton, IN at Wells Community Hospital in 1969.

When Miller arrived in 1961, Somalia was in a state of chaos. In 1963, the government outlawed the teaching of any religion other than Islam. This led to the exodus of almost all missions in Somalia, save the Mennonites. For this reason, Somalia was underserviced and the need for medical missionaries was great. Only the Mennonites helped to fulfill this need. Mennonite missions would be required to teach the Qur'an in order to maintain their status in Somalia. The Mennonites worked to maintain their place in Somalia by remaining cooperative. They began teaching English in the missions' schools beginning in the 1960s. Interestingly, Somalia did not have its own written language and did not create one until October 1972. On October 21, 1969, Major General Mohamed Siad Barre overtook the existing government. The Mennonite presence in Somalia began in the 1950s and has continued through the Eastern Mennonite Missions and Mennonite Central Committee. When Miller and his family arrived in 1969, there were five stable Mennonite missions in Somalia, and few other missions; Miller was the only American Doctor there. These locations included hospitals, boarding schools, and bookstores. Serving in the mission field, however, was sometimes dangerous. Merlin Grove, a white Mennonite missionary in Somalia during the 1960s, was stabbed to death while on duty in Somalia. This frightened some missionaries into leaving, but Miller and his family chose to continue their path.

Before arriving in Mogadishu, the Millers left their daughters, Shari and Marlis, and Miller's parents at Rosslyn Academy, a boarding school operated by the Mennonites outside of Nairobi. Miller's parents agreed to teach there for three years. In doing this, the elder Millers allowed Miller to continue on his journey and focus on the road ahead rather than spending his time raising a family. Miller, Mary, and their son, Stephen continued on to Mogadishu, Somalia. Once the Miller family arrived on August 26, 1971, they met with other missionaries in the city of Mogadishu.

The Jamama Hospital has now been converted into a donkey stable after civil war battles ravaged the country. Although the hospital no longer exists, Miller's contributions to the Somalian people are still remembered and the unwarranted 1972 trial will actually provide history with a record of Miller and his positive impact on the country.

Miller also worked with his daughter, Shari Miller Wagner, and wrote A Hundred Camels, published by Cascadia Publishing House in 2009. The book details the time Miller and his family served in Somalia before and during the trial.

The night before Miller and his family arrived in Africa, there was a car wreck on the road between Kismayu and Jamama. Four people were in a Toyota that toppled over—two men and two women. The driver, under the influence of alcohol, was unharmed. His passengers suffered from severe, as well as some minor injuries.

In 2015, Miller again worked with his daughter, Shari Miller Wagner, and wrote Making the Rounds, published by BookLocker.com. This book details the experiences Miller had while being the Doctor for the small town of Markle, Indiana.