HONG KONG — A Canadian man sentenced to death in China for drug smuggling intends to appeal, one of his lawyers said Wednesday, as a diplomatic rift between Canada and China deepened and information emerged about the man’s past drug convictions.

The man, Robert Lloyd Schellenberg, 36, was tried, convicted and sentenced on Monday in what one of his attorneys called a stunningly swift outcome. The hearing in Dalian, a port city in northeastern China, was a retrial ordered by an appeals court last month, after Beijing angrily denounced Canada for arresting a Chinese tech executive at the request of the United States.

Zhang Dongshuo, one of Mr. Schellenberg’s two defense attorneys, said his client was relatively calm when they met on Tuesday, despite the death sentence and the possibility that a geopolitical conflict could decide his fate. Mr. Schellenberg said during that meeting that he would appeal, Mr. Zhang said by telephone.

“His main point is that he is innocent, and he didn’t do what he’s been accused of doing,” Mr. Zhang said.