Zumwalt, who reported to CFO Brian Olsavsky, left the Seattle company last week, sources told CNBC.
Amazon did not immediately respond to an inquiry as to why Zumwalt left.
Zumwalt started his career at Bank of America and was later treasurer of Wind River, which Intel (INTC) - Get Report acquired for $884 million in 2009. He also sits on the board of the U.S. Tennis Association.
Last month, Amazon reported second-quarter revenue of $63.4 billion (up 20% annually) and GAAP EPS of $5.22. Revenue beat a consensus analyst revenue estimate of $62.52 billion, while EPS missed a consensus of $5.56.
The company guided for third-quarter revenue of $66 billion to $70 billion (up 17% to 24%), which compares favorably to a consensus of $67.28 billion at its midpoint. However, operating income guidance of $2.1 billion to $3.1 billion was below a consensus of $4.39 billion.
The shares were down 1.1% to $1,748.73.