Steve Burns was born in Boyertown, Pennsylvania. He played in bands called Sudden Impact US, Nine Pound Truck, and the Ivys (which he has called a "Morrissey rip-off band") while in high school and college. He studied theatre under an acting scholarship at DeSales University in Center Valley, Pennsylvania, in the Lehigh Valley. He dropped out of school and moved to New York City to become a professional actor. He lived in a basement apartment near Times Square, finding his first success as a voice-over artist for ads and making appearances on Homicide: Life on the Street and Law & Order.
In 1995, Burns auditioned for Blue's Clues. He showed up with long hair and an earring, later commenting that he was a bit of a skate rat. Initially, the Nickelodeon executives were not supportive of Burns hosting their new show; in subsequent auditions the show's creators requested that he dress more conservatively. Burns reported that the creators, in a call-back phone conversation, asked him, Could you not look like you tomorrow morning? It became apparent, however, that he was the favorite with preschool test audiences. Executive producer, co-creator and voice of Blue, Traci Paige Johnson reported that of the 100 people they auditioned, Burns was the realest. As Dr. Alice Wilder, Nickelodeon's Director of Research and Development, said, There was just something about this kid, who was fresh out of Pennsylvania, who just knew where to look in the camera to really talk to kids. He was just right.
From its premiere, Blue's Clues was an instant hit, due to Steve Burns' performances as much as the show's format. He became a superstar among his audience and their parents, but unknown to everyone else. However, enjoyed what he called being a "micro-celebrity, about as small a celebrity as you can be." As The New York Times reported, he "developed an avid following among both preteen girls and mothers. The former send torrents of e-mail; the latter scrutinize the show with an intensity that might make even Elmo, the red monster of Sesame Street, blush." In 2000, People magazine included Burns in their annual list of America's most eligible bachelors.
Burns became very involved with the production of Blue's Clues from the beginning. One of the most challenging aspects of being the host of the show was performing in front of the blue screen before the animation was added. Burns called it "maddening" and likened it to "acting at the bottom of a swimming pool."