Before its foundation, Ryuho Okawa had published various books of "spiritual messages" that claim to channel the words spoken by religious and historical figures such as Jesus Christ, Confucius and Nichiren.

[8] Members of Happy Science attend training courses (kenshūkai (研修会)) and "qualification seminars" (資格セミナー, shikaku seminā) in order to increase their level within the group's hierarchy.

They believe that the being was first born on Earth 330 million years ago and that it is the same entity that has been worshipped at different times as Elohim, Odin, Thoth, Ophealis (Osiris), Hermes and Shakyamuni Buddha, with Okawa himself as the current incarnation.

[16][17] The organisation has branches in several countries including South Korea, Brazil, Uganda, the UK, Australia, India and Singapore.

Happy Science has also released promotional videos claiming, without evidence, that North Korea and the People's Republic of China are plotting the nuclear destruction of Japan.

[18] The group has sold "spiritual vaccines", falsely claiming that they prevent and cure COVID-19, advertised virus-related blessings at rates from $100 USD to over $400 USD, and sold coronavirus-themed DVDs and CDs of Okawa lecturing, which make false claims of supposedly boosting immunity, as of April 2020[update].

After initially defying physical distancing measures, it later closed its New York temple, announcing that it had administered their fraudulent "vaccines" remotely.

[28] On February 10, 2022, the fifth chapter of anthology manga Kami-sama" no Iru Ie de Sodachimashita ~Shūkyō 2-Sei na Watashi-tachi~ ('A Home Life With God ~We Children Born Into Religion~'), written by Mariko Kikuchi as a criticism of Happy Science and other fringe religious organizations, was removed by the publisher, Shueisha following backlash from Happy Science.