Art Director for Hallmark Studio Cards in the 1950s, which redefined funny greeting cards for generations to come, outlined in loving detail in Dean Norman's 2004 book Studio Cards: Funny Greeting Cards and People Who Created Them. Due to staff turnover, Denney began illustrating cards as well, but found that his true love was lettering. His signature style of lettering was so popular during the 1960s that American Greeting Cards copied it and used it as filmset type on their own product line.