Stewart -- who had such hits as "Hot Legs," "Maggie May" and "Do Ya Think I'm Sexy?" -- won the Grammy Sunday for Best Traditional Pop Vocal Album for "Stardust ... The Great American Songbook Volume III."
Wilson -- who with the Beach Boys scored '60s hits including "I Get Around," "Fun, Fun, Fun" and "Surfin' USA" -- won his first Grammy for Best Rock Instrumental Performance for "Mrs. O'Leary's Cow," from his 2003 album "Smile."
"I waited 42 years for this Grammy," said Wilson backstage at the Grammys, "and it was so worth the wait."
Wilson was honored by the Recording Academy on Friday as its MusiCares Person of the Year. MusiCares is the academy's philanthropic arm, established to help music professionals in time of financial and personal need.
Veteran singer Nancy Wilson won her second Grammy -- 41 years after winning her first in 1964 for Best R&B Recording for "How Glad I Am." Wilson won Sunday for Best Jazz Vocal Album for "R.S.V.P. (Rare Songs, Very Personal)."