The Rev. William M. King, 81, a professor at St. Joseph's University and an expert on Latin America, died of heart failure Thursday at Manresa Hall, the Jesuit retirement residence in Merion.

Father King taught in the history department at St. Joseph's from the early 1970s to 1994.

"He was a gentle but exacting teacher," said Randall Miller, a colleague in the history department.

Father King, who was fluent in Spanish, was active with the Latin American Studies Program at St. Joseph's. He often spent summers and sabbaticals studying in South America, and ministering with the Jesuit communities there. He wrote a book about the history of Ecuador, where he spent extended periods of time, Miller said.

After leaving St. Joseph's, Father King lived for a year in Rome, where he helped edit an encyclopedia of Jesuit history. For 10 years, he was a prison chaplain and assisted the pastor at Immaculate Conception Church in Albuquerque, N.M. After retiring in 2005, he lived in the Jesuit residence at Georgetown University until last month.

A native of Pittsburgh, Father King attended Georgetown for two years before entering the novitiate in 1948. He was ordained in 1960. He studied philosophy at West Baden College in Indiana and theology at Woodstock College in Maryland, and earned a doctorate in Latin American history from the University of Texas.

Father King taught at Loyola High School in Towson, Md.; Loyola College in Baltimore; and the University of Texas before joining the St. Joseph's faculty.

He is survived by sisters Martha Cox and Catherine Tovey. His younger brother, the Rev. Thomas M. King, a Jesuit priest and professor of theology at Georgetown University for more than 40 years, died in June.

A Funeral Mass will be at 10 a.m. Monday at Dahlgren Chapel of the Sacred Heart, Georgetown University, 37th and O Streets N.W., Washington. Friends may call from 9. Burial will be in the Georgetown Jesuit Cemetery.

Contact staff writer Sally A. Downey at 215-854-2913 or sdowney@phillynews.com.