Gustave Moynier was born in Switzerland in 1826. He studied law in Paris where he received his doctorate in 1850. Because of his Calvanist upbringing, he became involved in social and charity work early on in his life. He became chairman of the Geneva Society for Public Welfare in 1859 and shortly after was sent a copy of Jean Henri Dunant's book "A Memory of Solferino" by Dunant himself. While he was very interested in Dunant's thoughts on creating an organization to assist wounded soldiers during battle, he did oppose some key ideas Dunant was in favor of. This led to what would be a lifelong rivalry between the two. A rivalry that would have a great affect on Dunant's entire life.

Moynier aided in the creation of an organization called the "Commission of Five". This commission was set up to discuss Dunant's ideas and possible implementation. Among the initial members were Moynier and Dunant, (Moynier being the Chairman). Early on the two butted heads over Dunant's idea to give neutral protection to all wounded soldiers and medical staff, regardless of whose side they were on. Moynier strongly opposed this idea from the beginning. The Committee of Five would evolve into and become the International Committee of the Red Cross with Moynier becoming the Vice President.

Intially, Dunant had some success getting top ranking political and military figures to implement his neutral protection ideas. This progress would come to a halt however in 1864 when Moynier became the Committee's president and led a movement to expel Dunant from the Committee. Dunant would soon fall on tough financial times and spend the rest of his life in debt.

Moynier would continue to be a nemesis of Dunant long after the expulsion. He would make several successful attempts at blocking financial assistance intended for Dunant. It is said that Henri Dunant spent the rest of his life, even his final final years, in fear of Moynier. Jean Henri Dunant ended up outliving his lifelong nemesis, Gustave Moynier, by just two months.