Martin Grolnic, 90, of Rockville, Maryland, died on July 3.

Born and raised in Philadelphia, Marty was the eldest son of the late Simon and Rose. He was predeceased by his wife of many years, Dorothea, of blessed memory, and his younger brothers, Alan and Sidney.

From a working-class family of modest means, Marty was the paradigm of a self-made man. He volunteered for the U.S. Army, stationed in Alaska on watch against the Cold War threat of Soviet invasion. He used his GI benefit to attend Temple University, graduating in 1959. He entered a career in sales, first as a junior salesman at Mack Trucks, then as a senior member of the team at Honeywell selling the first generation of corporate computers. Relocating to Potomac, Maryland, he joined Source EDP, a pioneering IT staffing firm, as their national capital regional manager.

Leaving corporate life in his mid-50s and throwing all sensible advice to the wind, Marty trusted to his salesmanship and business acumen to realize his lifelong dream of business ownership. He purchased and revitalized SEI, Inc. in Frederick, Maryland, which provides critical backup power systems for telecommunications, industrial, military and government customers. As president, he led the company for many years, not truly retiring until his early 80s. In its heyday, SEI provided a livelihood for 35 employees, a fact of which he was extremely proud.

He is survived by his children, Joseph, Steven and Robyn; and his grandchildren, Eli, Isaac and Ava. May his memory be a source of comfort and blessing to all who knew him. Arrangements entrusted to Torchinsky Hebrew Funeral Home.