He had a significant influence on the Canadian insurance industry (Great-West Life turned out be the second biggest insurance conglomerate in Canada, started the first Western Canada based insurance company), politics (rallied against high tariffs and the railway monopoly). During his tenure as managing director of Great-West Life the company"s share of sales in Canada"s insurance market rose from 0.5% to 13.8%. Business In 1890/1891 he founded Great-West Life, a direct response to rising discontent in Western Canada with the insurance industry (all of them were based in Eastern Canada and Canadian companies represented only 29% of the industry, that caused premiums to be very high).
He started the insurance company also because development by farmers and retailers in Western Canada needed capital funding and Jeffrey Brock who had lots of connection with farmers and other business people, wanted to help them.
He supervised the young, fast growing company which expanded to Eastern Canada in 1895 when it acquired Saint John based Dominion Safety Fund Life Association and the United States in 1906 when it began operating in North Dakota (American business became separate from Canadian operations in 1979 and became The Great-West Life & Annuity Insurance Company). Great-West Life was incorporated on August 28, 1891.
Brock led the company alongside Winnipeg mayor Alexander Macdonald who was its first president
He is a member of the Canadian Business Hall of Fame Companions.