Two Boston City Hall officials have been convicted of conspiring to extort the founders of the Boston Calling music festival, federal prosecutors said.

Kenneth Brissette, the city’s director of tourism, and Timothy Sullivan, chief of intergovernmental affairs, were charged in US District Court in Boston with illegally pressuring Crash Line Productions into hiring nine members of a stagehands union to please Mayor Martin J. Walsh, a former union leader with close ties to organized labor.

Jurors, who had deliberated for only a few hours, convicted Brissette of both charges he faced — Hobbs Act conspiracy and Hobbs Act extortion, according to US Attorney Andrew Lelling’s office. Sullivan was convicted of Hobbs Act conspiracy but acquitted of Hobbs Act extortion.