Complex sentence: Over the next few years he had several songs that did reasonably well on the country music charts and he continued to develop his career with performances at live country music shows as well as on radio and then on the all-important new medium, television.
Split into simpler sentences: Over the next few years, he had several songs that did reasonably well on the country music charts and he continued to develop his career with performances at live country music shows. He also did well on radio and then on the all-important new medium, television.