(CNN) -- Award-winning pianist Roger Williams, who played before nine U.S. presidents and recorded dozens of albums over his long career, died early Saturday in Los Angeles after a struggle with pancreatic cancer, his assistant said. He was 87. 

Jacque Heebner, Williams' personal assistant who said she had known the musician for 77 years, said she was with him inside his home when he died. Even into his final weeks, Williams continued to perform and to champion such causes as music education. He had recently released an album and was under contract for three more, she said. 

"There was never a man with a more tender, gentle heart," Heebner said. "He was a charming man, even at the age of 87." 

Born Louis Weertz in Omaha, Nebraska, the pianist attended Drake University and the Juilliard School in New York City. He then met Dave Kapp, the founder of Kapp Records, who suggested the musician change his name to Roger Williams, according to a biography on the Hit Parade Hall of Fame website. 

His break came in 1955 with his recording of "Autumn Leaves," going on to have hits on the Billboard charts for four decades, according to his official website. His records include "Born Free" and themes from the movies "Doctor Zhivago" and "Somewhere in Time." 

Williams' success helped land him a star on the Hollywood Walk of Fame, a 2011 induction into the Hit Parade Hall of Fame and many other honors. He was also a workhorse performer, including long stints headlining shows in Las Vegas in which he played his characteristic blend of originals, classics and works from greats like Duke Ellington and more contemporary composers. 
Was it a success?
His break came in 1955 with his recording of "Autumn Leaves," going on to have hits on the Billboard charts for four decades