Jack Welch, the architect of General Electric's (NYSE:GE) meteoric rise and champion of a number of business practices that were widely embraced by corporate America in response to GE's success, has died at the age of 84.

Welch joined GE in 1960 straight out of college after earning graduate degrees in chemistry and steadily worked his way up the ranks. He was named CEO in 1981, and over a twenty-year career made more than 600 acquisitions, including expanding GE's reach into broadcasting and building its financial operations, among other areas.

Front of a GEnx engine.

Aircraft engines, including the GEnx Engine, are a key part of GE's portfolio. Image source: General Electric.

Welch was also known for advocating the "Six Sigma" quality control program, popularizing it in corporate America. He was given the nickname during his early days at GE as "Neutron Jack" for his job cutting and streamlining actions, but the results transformed a stogy industrial company into a growth stock.

GE's market capitalization grew from $12 billion to $410 billion during his tenure. Fortune magazine in 1999 named Welch "manager of the century."

Following his career at GE, Welch spent time as an advisor to private equity firms. He and his wife Suzy also cowrote a long-running column for BusinessWeek and authored books on management, with the two in 2009 establishing the Jack Welch Management Institute.

Welch's successors at GE have not been able to sustain his success, with the company's shares off 71% from where they traded at the end of 2001. Critics have complained GE grew too complex and took on too much debt. GE is now on its third CEO since Welch stepped down.