One of the most influential and admired business executives of his generation—and the poster boy for the hypercompetitive star CEO of the '80s and '90s—Welch is the retired chairman and CEO of General Electric.

Welch earned a PhD in engineering from the University of Illinois before joining General Electric in 1960. By 1972, he was a vice president at the company, moving up the ladder to vice chairman in 1977 and chairman and CEO in 1981. During his two decades running the show, Welch transformed GE from a sleepy electronics company into a global powerhouse conglomerate, thanks to a ruthless management approach which involved continually weeding out managers who failed to perform up to snuff. Empowering his talented division heads to run their units like independent companies, Welch groomed a generation of future CEOs and modernized GE by shifting the company's focus from manufacturing to financial services (GE Capital) and media (NBC).

Welch's obsessive focus on earnings, his embrace of the Six Sigma approach, and his Darwinian management tactics earned him legions of fans among consultants and business journalists. (He was named "Manager of the Century" by Fortune magazine in 1999.) Not everyone was so convinced, however. His unrelenting focus on the bottom line led to a handful of legal ordeals as managers took shortcuts to achieve earnings, and some critics have argued that Welch's emphasis on short-term gains occasionally came at the expense of longer-term opportunities. Welch is quasi-retired these days. He's a special partner at the private equity firm Clayton, Dubilier & Rice, founded the Jack Welch Management Institute, and has written columns for BusinessWeek and Fortune with his wife. [Image via Getty]