Investors could get disappointed and market sentiment could quickly turn if President Donald Trump slows down on his current bout of policy execution, a former Federal Reserve governor told CNBC on Thursday.

Market players have shown signs of confidence on the potential economic benefits of the new U.S. administration with Trump promptly putting forward many of his campaign pledges. As a result, the Dow Jones reached an all-time high on Wednesday and broke the psychological 20,000 mark. But such a trend could reverse very easily, says Randy Kroszner, professor of economics at the University of Chicago.

"I think there are very high expectations for executions on some of the economic parts of the program, cutting taxes, trying to rationalize their taxes to bring some of the $2 trillion trapped offshore to onshore, de-regulation," he said.