Lee, a former Superior Court judge, received 254 votes, or 76 percent. He defeated Michael Protack, an airline pilot, who received 79 votes, or about 24 percent.
A candidate must have 60 percent of the vote to win the party's endorsement. The candidate will be formally chosen in the Republican primary in September.
Lee failed to win the party's gubernatorial endorsement four years ago, then waged a grassroots primary campaign that brought him within a whisker of the nomination.
Lee told convention delegates he was gratified by their confidence in him. "I believe that I've been called to this purpose," he said.