Former General Electric CEO (GE  ) John Francis Welch Jr., better known as Jack Welch, passed away on Sunday at the age of 84. Welch, who was chief executive at GE from 1981 to 2001, was notable for helping GE to become one of the most valuable companies in the world, expanding both its operations and its stock price considerably during his tenure.

Welch was born on Nov. 19, 1935, in Peabody, Massachusetts, to Grace and John Francis Welch Sr. His mother, Grace, was a homemaker, and his father Jack was a conductor with the Boston & Maine Railroad. Welch worked several odd jobs in his youth, working as a paperboy, golf caddie, and a shoe salesman, among other jobs.

Welch studied at the University of Massachusetts Amherst, graduating with his bachelor's in chemical engineering, and would later attend the University of Illinois where he would obtain his Masters and Ph.D. in Chemical Engineering.

Welch would first join General Electric in 1960 as a junior chemical engineer at the company's branch in Pittsfield, Mass. Welch's tenure at GE was almost cut short by his dissatisfaction with GE's considerable bureaucracy, though he was convinced to stay with the company by executive Reuben Gutoff, who promised he would help Welch to streamline GE.

In 1968 Welch became the Vice President of GE's Plastics Division, which would begin his upward trek through the ranks of the company. Welch would become Vice President of the Metallurgical and Chemical divisions in 1971, and in 1973 was named Head of Strategic Planning. Welch as then named Senior Vice President and Head of the Consumer Products and Services division in 1977, quickly becoming Vice Chairman of GE in 1979 before, finally, becoming CEO of GE in 1981, being the youngest executive to attain the position.

Welch immediately set out to streamline GE, gutting the massive bureaucracy at the company and laying off thousands of workers in the process, earning the name "Neutron Jack," after the neutron bomb, an atomic weapon that uses radiation over explosive power to kill people without damaging cities; Welch would not look upon this nickname kindly, however. Welch would then expand GE by leaps and bounds, acquiring numerous companies such as RCA and Kidder Peabody. GE would even create its financial division with GE Capital. Under Welch's control, the company went from $27 billion in revenue to $130 billion, while its market capitalization went to $410 billion from $14 billion. Welch would retire from GE in 2001.

While Welch turned the company around and had immense success at the helm of GE, his tenure was not without its faults. Welch's retirement benefits from GE became the target of public scrutiny, largely due to the unlimited use of GE jets, office space, among other benefits. Additionally, GE Capital had grown too large under Welch's tenure and cost the company quite a bit.

Jack Welch leaves a considerable legacy in his wake, turning GE into a mammoth household name that became synonymous with home appliances and electronics. Even today, many corporate executives follow Welch's example, abiding by his principles of betting on promising talent and streamlining companies for greater efficiency.