His first feature film role was probably in the 1975 gay adult filmBoynapped!. He subsequently appeared mostly in straight porn films shot in New York such as Barbara Broadcast, Jail Bait,Summer of Laura,Punk Rock,Marishino Cherries, and Teenage Pajama Party. Posa was credited as Wade Nichols in most of the adult films in which he appeared.
In 1979, using the name Dennis Parker, he recorded a disco album on Casablanca Records entitled Like an Eagle. The album was produced by Village People creator / producer Jacques Morali. The title track was released as a single, and appears on the 1994 box set The Casablanca Records Story.
Posa (still as Dennis Parker) also joined the cast of the soap operaThe Edge of Night in 1979, as Police Chief Derek Mallory.
Seriously ill by October 1984, Posa was unable to continue working on The Edge of Night and his character was written out of the show. The date of his death is commonly reported as January 28, 1985, but the Social Security Death Index indicates that Posa died in March of that year. According to a persistent rumor the cause of death was a self-inflicted gunshot wound, but this has never been confirmed. An obituary article printed days after his untimely death notes that he succumbed after a "brief illness, most likely complications due to AIDS."