The most popular TV version of the Hardy Boys, officially titled The Hardy Boys/Nancy Drew Mysteries, featured Shaun Cassidy as Joe Hardy and Parker Stevenson as Frank Hardy. This series ran for three seasons from 1977 until 1979 and included 46 total episodes, with 43 including Cassidy and Stevenson.
Other TV versions of the Hardy Boys didn't last as long as the 1977 version. From 1969 until 1971, a 34-episode series featured Byron Kane as Frank Hardy and Dal McKennon as Joe Hardy. A 1995 version of the show featured Paul Popowich as Joe Hardy and Colin K. Gray as Frank Hardy.