In 1952, Kirsh began assisting his mother with the operation of his father's original malt factory in Potchefstroom, then, in 1958, launched his own first venture, founding a corn milling and malt business in
Eswatini. As of August 2018, Kirsh owned 75 percent of Jetro Holdings, which had about 115 Jetro Cash & Carry and Restaurant Depot stores in the United States. Kirsh Holdings Group, Kirsh's primary holding group, continues to own half of Swazi Plaza Properties. In 2009, Kirsh was a director and held a 24.2 percent stake in Magal Security, which met controversy by providing fences in Israel. In 2014, Kirsh sold his 40 percent stake in Magal to FIMI. Kirsh left South Africa in 1986, after selling much of Kirsh Industries to
Sanlam, In 2006, his companies included Mira Mag and Ki Corporation. Through Kifin Limited, part of Ki Corporation, by 2008, he also held a stake in
Minerva, dropping a bid for majority ownership in 2010. By early 2018, Kirsh retained retail and property interests in Britain, the United States, Australia, and Eswatini. In March 2026, Sysco contracted to acquire Jetro Restaurant Depot LLC, for $29.1 billion, including debt, with its shareholders to receive over 14 times its operating income, as $21.6 billion in cash, together with 91.5 million shares, representing about 16% of Sysco's stock. Jetro reported $2.1 billion in earnings from $16 billion in revenue in 2025, and is expected to change ownership within a year. ==Personal life==