[4] He was included in Forbes's 2023 list of the United States' Most Generous Givers, according to which he has donated $1.56 billion to various charitable causes, primarily in education, economic mobility and medical research.

[10] In a 1986 article in the Sun-Sentinel, he said he thought he would become a businessman or lawyer and that he believed the job market for computer programmers would significantly decrease over the coming decade.

[9] Despite a ban on running businesses from campus, Griffin convinced school administrators to allow him to install a satellite dish on the roof of Cabot House, a dormitory, to receive stock quotes.

[11][9] He also asked Terrence J. O'Connor, the manager of convertible bonds at Merrill Lynch in Boston, to open a brokerage account for him with $100,000 that Griffin had gotten from his grandmother, his dentist, and others.

[17] From the time of his second marriage to Anne Dias in 2003 until late 2009, Griffin was the lead investor in Aragon Global Management, a hedge fund run by his then wife.

[32] On January 25, it was announced that Citadel would invest $2 billion into Melvin Capital, which had suffered losses of more than 30% on account of its short positions, particularly on GameStop.

[49] He serves on the board of trustees at the Whitney Museum of American Art in New York, whose lobby bears his name: Kenneth C. Griffin Hall.

[53] In 2022, he created the Ukraine Math and Science Achievement Fund with $3 million, which supports young Ukrainian refugees studying at Cambridge University.

[56] In March 2020, in response to the COVID-19 pandemic, Griffin contributed $2.5 million to support food services for children in Chicago Public Schools.

[57] In May 2020, Griffin and his partners at Citadel made a £3 million donation to help develop a COVID-19 vaccine and to support NHS Nightingale Hospitals.

[58] Griffin oversaw a $2 million donation from Citadel to Weill Cornell Medicine to help fund the development of new ways to protect people from COVID-19 and identify new cases of the illness.

[59][better source needed] Griffin has worked with the Bill and Melinda Gates Foundation to promote charter schools in the U.S.[9] and fund tutoring.

[71] In November 2021, Griffin outbid a group of crypto investors to purchase the last privately held copy of the United States Constitution at auction for $43.2 million.

[72][73] In March 2022, Griffin donated $40 million to the American Museum of Natural History in New York to help complete the 230,000 square foot renovation.

[76] Griffin, the Carnegie Corporation of New York, and the Walton Family Foundation have funded The Education Recovery Scorecard, an analysis of pandemic learning loss released in October 2022 that uses local and national test score data to map changes in student performance.

[81] In April 2024, Griffin donated $9 million to fund a math-tutoring program for students in the Miami-Dade County Public Schools, in partnership with the University of Chicago and Accelerate, to address education gaps caused by the COVID-19 pandemic.

[87] In May 2022, The University of Chicago announced a $25 million donation from Griffin to launch an initiative design to train police managers and prevent neighborhood violence.

The Policing Management Academy aims to professionalize departments by educating their leaders though coaching, accountability and data-driven decision making.

[91] In early 2023, Griffin gave $25 million, his largest single donation to date in Florida, to the Nicklaus Children's Hospital in Miami.

[102] In November 2018, Griffin criticized Trump's tweets berating Chair of the Federal Reserve Jerome Powell, calling them "completely inappropriate for the president of the United States".

[110][111] In an October 2020 email to Citadel LLC's Chicago employees, Griffin criticized Pritzker's tax plan and alluded to the possibility of moving his company out of Illinois.

[112][113] While being interviewed by Paul Tudor Jones at the Robin Hood Foundation investor conference in October 2020, Griffin criticized Joe Biden's plans to raise the long-term capital gains tax rate.

He also supported statements made by fellow alumnus and donor Bill Ackman that his firm would not hire students who signed the letter.

[117] In May 2024, he criticized the "failed education system" for anti-Israel protests on campuses, urging Harvard to "embrace our Western values that have built one of the greatest nations in the world".

[121] Griffin contributed $2 million to the Freedom Partners Action Fund, a Republican-aligned super PAC backed by Charles and David Koch, in November 2015.

[192][193][194] In 2015, Griffin purchased two apartments at the top of the Faena House, a condominium on Collins Avenue in Miami Beach, Florida for $60 million.

[201][202][203] In 2019, Griffin set the record for the most expensive residential sale ever closed in the U.S. when he purchased roughly 24,000 square feet across three floors at 220 Central Park South in Midtown Manhattan for $238 million.

[107] Griffin has spent $450 million to assemble one of the largest private waterfront sites in Palm Beach County, Florida, with plans to build a 50,000 square foot estate.

Griffin provided the trading savvy, working both out of his Harvard dorm room and at home in Florida, while Simonson allegedly created the computer program that served as its technological backbone.

Griffin claims the original script contained many fabrications, and he coordinated with Sony Pictures to correct some inaccuracies before its release, but he still finds aspects of the film to be sensationalized.