Once known for grim letters to fellow wealthy Americans warning of socialist apocalypse, Charles G. Koch now promotes research on the link between freedom and everyday happiness. Turn on “The Big Bang Theory” or “Morning Joe,” and you are likely to see soft-focus television spots introducing some of the many employees of Koch Industries.

Instead of trading insults with Harry Reid, the Democratic Senate leader, Mr. Koch and his brother, David H. Koch, are trading compliments with President Obama, who this month praised the Kochs’ support for criminal justice reform at a meeting of the N.A.A.C.P.

After two elections in which Democrats and liberals sought to cast them as the secretive, benighted face of the Republican Party, the Kochs are seeking to remake public perceptions of their family, their business and their politics, unsettling a corporate culture deeply allergic to the spotlight. Even as their donor network prepares to spend extravagantly to defeat Democrats during the 2016 campaign, the Kochs have made cause with prominent liberals to change federal sentencing rules, which disproportionately affect African-Americans, while a Koch-backed nonprofit, the Libre Initiative, offers driving lessons and tax preparation services to Latinos.

This fall, Charles Koch will publish “Good Profit,” a new book about his management philosophy and worldview that seems intended to introduce the Kansas-born Mr. Koch as a kind of libertarian sage of Wichita. The makeover attempt has even included the Kochs’ twice-yearly “seminars” for donors to their political operation, events previously shrouded in such secrecy that Koch aides once erected large fans around an outdoor pavilion to foil long-distance recording devices. At this year’s summer seminar, which begins Saturday in Dana Point, Calif., invited reporters will be allowed to attend some sessions, including those featuring many of the Republican Party’s presidential candidates.