[7][8] He received a BA in economics and Spanish from the University of North Carolina at Chapel Hill (UNC-CH) in 1985, and an MBA from Harvard Business School in 1991.

From 1992 to 1997, he was an investment banker at Merrill Lynch,[2] where he specialized in global corporate finance, and mergers and acquisitions in the financial services sector[10] in Latin America,[2] the United States and Europe.

[10] In 1997, Buchan joined hedge fund Maverick Capital,[2] where he handled its investments in banks and financial services companies.

[13] Buchan closed one of his funds in December 2011[14] due to losses stemming from the European debt crisis,[2] and returned money to investors.

[20] In November 2019, he traveled to Venezuela's border with Colombia to bring eyewitness attention to the humanitarian crisis caused by the regime of Nicolás Maduro and his primary ally, Cuba.

"I saw pregnant Venezuelan women waiting to give birth in an extremely overcrowded maternity ward," Buchan wrote in the Spanish language newspaper El Mundo.

"[21] Buchan met interim Venezuelan President Juan Guaidó in Madrid to reiterate the United States' strong support for the National Assembly.

The fund has helped students and professors further their research on topics in Spanish culture and linguistics, and also enabled them to travel to Spain as well as other Spanish-speaking countries.

[9] In 2012, The Buchan Excellence Fund supported the UNC-CH Department of Romance Languages and Literature's project 21st Century Pen Pals, a video exchange program between American and Spanish schoolchildren.

Buchan was vice-chair of the UNC-CH Arts and Sciences Foundation Board of Trustees, is a member of the Chancellor's Philanthropic Council, and serves on the university's Campaign Planning Cabinet.