Formerly a pastor and high school president in the Archdiocese of Miami, he served as bishop of the Diocese of Pueblo in Colorado from 2009 to 2013.
After graduation, Isern got a job in marketing with First National Bank of Miami, promoting the introduction of ATM machines in Florida.
[2] In 1999, Isern became an adjunct professor at St. Vincent de Paul Regional Seminary and assistant chaplain for the archdiocesan Youth Center and for Encuentros Juveniles.
[5] On October 15, 2009, Isern was appointed the fourth bishop of the Diocese of Pueblo by Pope Benedict XVI.
[7] On June 13, 2013, Pope Francis accepted Isern's resignation due to poor health as bishop of the Diocese of Pueblo.