Born in 1956, Jimmy Johnson was surrounded by music from an early age; his father a professional bass player with the Minnesota Orchestra and his mother a piano teacher. He is an important figure in the history of the instrument as he had a big role to play in Alembic's development of one of the first 5 string basses (strung with a low B string).
In terms of playing style, the guy can do it all. He has a vast musical base to draw from allowing him to slot easily into any musical situation from pop to prog rock. His versatility probably stems from the classical training he would have got from his parents. The ability to read music, observe dynamics, study difficult music as well as build up technical facility would have stood him in good stead in his session career. He mainly uses traditional fingerstyle using the index and middle fingers, using different hand placements to alter his tone.
What I love about him is that he knows exactly what to play in diverse musical situations. Listen to the note choice and placement on 'You've Got A Friend In Me' from Toy Story.
Compare that to Five Elements from Derek Sherinian's Oceana album:
He is perhaps best known as the bass player for James Taylor. This album captures the band brilliantly:
Jimmy is a really good example of how working on your all round musicianship alongside your technical skills can allow you to be able to step into a variety of musical genres without any problems. For some pointers on what to learn from listening to different styles of music, read this post.