He is the eldest of three children born to Patricia (Patti) and James Buchanan, a businessman.

After receiving his Master of Business Administration degree, Buchanan worked as a retail consultant at Accenture from 1996 to 2004.

[8][9] In February 2017, Buchanan was named chief merchant of Walmart's Sam's Club business unit.

[7] In 2019, Buchanan was named executive vice president and chief merchandising officer of Walmart.com, where he was part of the effort to invest in Walmart's digital shopping experience, to compete with online giant Amazon.

[3] In 2020, Buchanan joined The Michaels Companies as the chief executive officer and a member of the board of directors.