Within the TV show, Joe is a year younger than his brother, Frank Hardy (1977 TV); his mother is dead, and Aunt Gertrude lives with the family to help raise the boys. During first & second seasons, he was shown as a reluctant hero, not wanting to get into trouble and having a decided pacifistic streak (usually shoving Frank out front during any trouble), though very much the heart-led of the pair, with a deadpan snark sense of humor. In the show, he's shown to be an expert on fingerprints and forensics, with knowledge of chemistry, electronics, and photography.
Third season saw Joe becoming more action-oriented and emotional, more likely to chase down and punch out the bad guys.
Joe was played by Shaun Cassidy