Now, the company’s aggressive ways have been cast in a new light. The United States has accused Meng Wanzhou, a top Huawei executive and daughter of its founder, of committing bank fraud to help the company’s business in Iran.

It is not clear precisely how Huawei’s culture shaped its dealings in Iran. But an intense will to get ahead, which helped propel it to the head of the global market for telecom network equipment, seems to have informed employees’ actions in previous cases that put the company under scrutiny.

Huawei workers have been accused of bribing government officials to win business in Africa, copying an American competitor’s source code and even stealing the fingertip of a robot in a T-Mobile lab in Bellevue, Wash. In 2015, Huawei’s founder and chief executive, Ren Zhengfei, said that as part of a company amnesty program, thousands of employees had admitted to violations ranging from fraudulent reporting of financial information to bribery.

In an emailed statement, a spokesman said that Huawei requires all employees to study and sign guidelines on business conduct every year. “At the heart of the guidelines is the principle of acting in accordance with all local laws and regulations,” said the spokesman, Joe Kelly. “Where employees are found to have acted outside these guidelines, the company takes decisive action which can include immediate termination of employment.”

Mr. Ren said in 2015 that Huawei had toughened its safeguards against employee misconduct. But the following year, in a speech that was emailed to employees, he acknowledged that many workers did not pay attention to internal rules and controls — perhaps, he said, because Huawei used to evaluate staff solely according to how much business they won.