James Anthony Zusy was born in Milwaukee, Wisconsin, on July 8, 1932, being the younger of the two sons of Joseph W. Zusy, Jr. and Ludmilla B. Wuchterl. His early education was at St. Anne 's Grammar School, Milwaukee, the parish in which he grew up. He attended St. John Cathedral High School, Milwaukee, and upon graduating in 1950, spent two years at Loras College, Dubuque, Iowa, before entering the Dominican novitiate.

On August 30, 1952, he received the habit at St. Peter Martyr Priory, Winona, Minnesota, and was given the religious name Bonaventure. His older brother, Father Dennis R. Zusy, O.P., had taken the same step four years previously. On August 31, 1953, he made his first profession of vows and was transferred to St. Thomas Aquinas Priory, River Forest, Illinois, for philosophical studies, where he earned a bachelor's degree at the Pontifical Faculty of Philosophy. He made his solemn profession there on August 31, 1956, and was immediately transferred to St. Rose of Lima Priory, Dubuque, Iowa, for four years of theological studies. Archbishop Leo Binz of Dubuque ordained him a priest at the priory chapel on May 23, 1959.

Father Zusy carried out his priestly ministry in three distinct phases. First, after completing theological studies, he was assigned to mission work in the provincial Vicariate of Nigeria, where he served in a number of locations for short periods of time, his major assignments being assistant pastor at St. Dominic Parish, Yaba (1960-67) and pastor of Our Lady of Fatima Parish, Gusau (1967-68.) During this time he also undertook the editing of the Vicariate newsletter, Nigeria.

The second phase of his priestly ministry, which consisted of pastoral work in the United States, began upon his return from Nigeria in early 1968. For a short time he did supply work, serving as chaplain at Rogers Memorial Hospital, Rogers, Arkansas, and assisting at St. Margaret Parish, Boyce, Louisiana, and St. Joseph Parish, Ponchatoula, Louisiana. In August of 1968 received a permanent assignment as assistant pastor at Nativity Parish, Campti, Louisiana, and after two years was named pastor of St. Margaret Parish, Boyce, where he served until 1976. His pastoral ministry had underscored for him the great need for canon lawyers to do marriage work and so in 1976 he began the third phase of his priestly ministry.

For four years (1976-80) he pursued studies in canon law at St. Paul University, Ottawa, Ontario, Canada, where he earned the J.C.D. degree. In 1980 he began his marriage work serving successively in various diocesan marriage tribunals: for four years (1980-84) he was stationed in New York City and served as associate presiding judge for the Tribunal of the Military Ordinariate; for three years (1984-87) as the Judicial Vicar of the Diocese of Fort Worth, Texas; for eight years (1987- 1995) as associate Judicial Vicar for the Archdiocese of St. Paul and Minneapolis, Minnesota; and then for nine years (1995-2004) on the Tribunal of the Diocese of Lexington, Kentucky. During his time in Minneapolis his brothers at Holy Rosary Priory, his residence, twice elected him as prior of the community.

Father Zusy was preparing to leave Lexington, Kentucky, and take up a position on the Metropolitan Tribunal of the Archdiocese of Detroit at the time of his unexpected death. While visiting friends in Dubuque, Iowa, he died of heart failure late on the afternoon of July 3, 2004. A wake and funeral Mass were held at St. Pius V Church, Chicago, Illinois, on July 7, 2004, and burial followed in the Dominican plot at All Saints Cemetery, Des Plaines, Illinois.