He began his professional acting career playing Billy Abbott in the original miniseries Rich Man, Poor Man. He went on to star in three nighttime television series: Executive Suite, Married: The First Year, and performed the role of Mitch Cooper (husband of Lucy Ewing Cooper) on the CBS nighttime soap opera Dallas. McCloskey was a series regular from 1980–1982, and made brief appearances in 1985 and 1988.

The Hieroglyph of the Human Soul is composed in what McCloskey calls “Watcher Language.” In 2003, the Watcher Language was granted copyright as a graphic language.

In 2003, McCloskey published the book Tarot ReVisioned through Olandar Press. It serves as an exegesis for his pen-drawn black-and-white interpretation of the Hermetic Tarot. In it, he discusses “paths of initiation, myth of origins and the profound philosophical implications of symbolism, Hermeticism, alchemy and the Grail.”

In 2018, McCloskey’s home was threatened during the Woolsey Fire. With the help of fellow soap opera star A Martinez, McCloskey was able to defend his home from destruction by the fire.