He literally played on hundreds upon hundreds of albums and songs with little or no recognition as part of "The Wrecking Crew" (as was Leon Russel) which was sort of the West Coast equivalent of "The Nashville Cats."
A lot of people forget that he joined the Beach Boys for one of the greatest albums in rock history - Pet Sounds. He also provided the backing guitar for "Classical Gas" and numerous other hit songs of the 60's and 70's before becoming famous in his own right.
Can't forget his place in movie history, playing the Texas Ranger in the original True Grit.