Dallin was born in Springville, Utah Territory, to a family then belonging to The Church of Jesus Christ of Latter-day Saints (LDS Church). As a boy he had lived among the Indians in prairies of the Far West, and had learned their language.
Cyrus studied sculpture in Boston with Truman Howe Bartlett and in Paris, with Henri Chapu and at the Académie Julian.
After studies he returned to Boston to become an instructor in modelling in the state normal art school.
In 1883, he entered the competition for an equestrian statue of Paul Revere for Boston, Massachusetts. He won the competition and received a contract, but four versions of his model were rejected. The fifth version was accepted only in 1899.
He accepted commision to work on the sculpture of angel Moroni for the spire of the LDS Church's Salt Lake Temple. The work was finished in 1893.
In Boston, he gained the respect of the other famous artists of his day, including Augustus St. Gaudens and John Singer Sargent. He became internationally famous, and his works were widely duplicated and collected.
He taught for a year at the Drexel Institute in Philadelphia, Pennsylvania, while completing his Sir Isaac Newton (1895) for the Library of Congress. He entered a Don Quixote statuette in the Salon of 1897, and Medicine Man in the Salon of 1899 and the Exposition Universelle (1900).
In 1900, at the age of 39, Dallin moved to Arlington, Massachusetts, which remained his home for the rest of his life.
He is best known for his plastic representations of the North American Indian-especially for "The Signal of Peace" in Lincoln Park, Chicago and "The Medicine Man, " in Fairmount Park, Philadelphia. His work "The Medicine Man" was exhibited in Paris, 1900 and won a gold medal. The full-size plaster version of The Protest was exhibited at the 1904 Louisiana Purchase Exposition, where it won a gold medal. At the 1904 Summer Olympics in St. Louis, Missouri, Dallin competed in archery, winning the bronze medal in the team competition.
He was a member of the National Academy of Design.
He married Vittoria Colonna Murray in 1891.
