Sullivan in the new role will succeed John Miller, was promoted last month to the newly created position of head of banking for the Americas.
A Barclays representative confirmed the contents of the memo, which was sent to staff on Monday. A copy of the document was seen by Reuters.
Sullivan joined the firm in 1998 as part of the industrials group and transitioned in 2003 to financial sponsors coverage, which includes building relationships with private equity firms. Among other transactions, he worked with Blackstone Group LP on leveraged buyouts and subsequent initial public offerings of both Pinnacle Foods Inc and SeaWorld Entertainment Inc.
Sullivan will work alongside Karen Frank and Ken McGrath, who have been appointed co-heads of financial sponsors group for Europe, Middle East and Africa.
Matt Grinnell, who has run the business since 2009, will become chairman of EMEA Financial Sponsors.
Soyoung Kim is a reporter for Reuters News in New York