Wilson Feng said he no longer even wants to stay in investment banking after losing sleep the whole time he was working in a top role at Merrill.
Forty-year-old Mr Feng said it was time for a career change and is considering working at a state-owned company in China rather than staying in the banking world.
"It's a nightmare," Mr Feng told Bloomberg. "My father won't recognise me if I stay in investment banking. I didn't see him for almost three years. I want to change my life."
"I never had five hours sleep during these four years," he added. "Salaries at state-owned enterprises are low compared with investment banking, but you can have a better life.''
After joining Merrill Lynch in 2004 as a junior banker, Mr Feng was promoted last year for helping the bank win a role in Industrial and Commercial Bank of China's $16 billion Hong Kong stock sale.
During his time in the role 70 per cent of Mr Feng's time was spent on executing deals.
Bloomberg calculates that Merrill was the premier arranger of China share sales in the US last year, in a market worth $60 billion.
Damian Chunilal, head of Pacific Rim investment banking, who hired Mr Feng said it was sad to see him go and that he would remain "a friend" of Merrill Lynch.