The reason the words In God We Trust is on money is because President Dwight D Eisenhower signed into law H.R. 619, a bill that required that the inscription “In God We Trust” appear on all paper and coin currency.
During the Cold War era, the U.S. government tried to distinguish itself from the Soviet Union, which promoted state-sponsored atheism.
The 84th Congress of 1956 passed a joint resolution "declaring IN GOD WE TRUST the national motto of the United States." "In God We Trust" appeared on all American currency after 1956.
Its use on U.S. currency dates to the Civil War.
Though opponents argue that the phrase amounts to a governmental endorsement of religion and thus violates the establishment clause of the First Amendment, federal courts have consistently upheld the constitutionality of the national motto.
The wording In God We Trust was put on American Currency on July 30th 1956.
The law and United States Code at 36 U.S.C. § 302, states that In God We Trust is a national Motto.
The law was signed by President Eisenhower on July 30th 1956.