Americium was first isolated by Glenn T. Seaborg, Leon O. Morgan, Ralph A. James, and Albert Ghiorso in late 1944 at the wartime Metallurgical Laboratory at the University of Chicago (now known as Argonne National Laboratory). The team created the isotope Am by subjecting Pu to successive neutron capture reactions in a nuclear reactor. This created Pu and then Pu which in turn decayed into Am via beta decay.
Seaborg was granted a patent for "Element 95 and Method of Producing Said Element," whose unusually terse claim number 1 reads simply, "Element 95.

Americium is widely used in commercial ionization-chamber smoke detectors as well as in neutron sources and industrial gauges.