Enbridge Inc.’s chief executive touted the Canadian company’s efforts to further expand in the United States – on the Gulf Coast and elsewhere – as part of a bid to capitalize on expected long-term natural gas demand in North America and overseas.

The Calgary, AB-based company, already a major force in Canadian and American energy, said a string of previously announced agreements with Dominion Energy Inc. would bolster its gas utility operations throughout several U.S. states. Enbridge is buying East Ohio Gas Co., Public Service Co. of North Carolina Inc., as well as Questar Gas Co. and its Wexpro Co. affiliate.

In all, the Dominion units on the sale block serve 3 million customers across 78,000 miles of pipelines with customers in Idaho, North Carolina, Ohio, Utah and...