Sambu graduated from Biwott Secondary School in 2006, where he ran for the cross-country team. Recognizing his exceptional abilities, Sambu's Coach encouraged him to join a running camp during the school holidays. Sambu's breakthrough came when he participated in a times trail race organized by American coaches seeking to offer athletic scholarships to talented Kenyan runners. Sambu won the race over a field of 100 runners and was soon after offered a full athletic scholarship to attend Rend Lake Community College.

While at Rend Lake, Sambu ran for both the Cross-Country and Track & Field Teams, capturing 10 Individual National Championships, including two NJCAA National Cross-Country Titles.

After graduating from Rend Lake in 2010, Sambu transferred to the University of Arizona, continuing his athletic journey while pursuing a bachelor's degree in Agricultural Economics. During his time at UA, Sambu was mentored by legendary Coach, James Li, who is known for his work with international runners. In his first year at Arizona, Sambu finished Runner-up in the NCAA National Cross Country Championships. During the Track season, Sambu took third place in the 3000m at the MPSF Indoor Championships and also placed third in the 5000m NCAA Championship (a UA school record). During the outdoor season, Sambu set a new school record in the 10,000m while winning his first Pac-10 Championship Title in the 10,000m and later finishing third in the NCAA Outdoor Championships. During his final year at UA, Sambu earned All-American honors in the 3000m and 5000m during the Indoor season. In the Outdoor season, Sambu repeated as the Pac-12 Champ in the 10,000m and was the Runner-up in the NCAA Championships. He also earned All-American honors in the 5000-meter run.

After graduating in 2013, Sambu continued to train under Coach Li, running in Half-Marathons, road races, and later full Marathons. While running, Sambu was offered a contract from Nike and ran for them for the following three years.

Beyond his athletic achievements, Sambu is a proud father of two boys, Jayden and Jeremy, and enjoys running with them on the weekends. Most recently, Sambu has been a volunteer coach at the University of Arizona while continuing to train and run in various long-distance events.