It was a curious moment last year when Carlyle Group Inc., once famous for bold bets on defense contractors, hired one of the more prominent names in socially responsible investing. Megan Starr is a Goldman Sachs Group Inc. alum known to appear on stages at gatherings like the SXSW film festival to proselytize the virtues of environmental, social and governance investing. Now she's at a firm with no plans to join the rush of private equity titans launching impact funds. Instead, Carlyle says, the 32-year-old is going to help reshape its broader portfolio. Carlyle Group is wading into the ESG movement with a markedly different strategy than rivals such as KKR & Co., TPG and Bain Capital, which have set up dedicated funds to make impact investments.