The cause was mesothelioma, said his manager, Patrick Rains.
The Jazz Crusaders, who played the muscular, bluesy variation on bebop known as hard bop, had their roots in Houston, where Mr. Sample, the tenor saxophonist Wilton Felder and the drummer Nesbert Hooper (better known by the self-explanatory first name Stix) began performing together as the Swingsters while in high school.
Mr. Sample met the trombonist Wayne Henderson at Texas Southern University and added him, the bassist Henry Wilson and the flutist Hubert Laws — who would soon achieve considerable fame on his own — to the group, which changed its name to the Modern Jazz Sextet.
The band worked in the Houston area for several years but did not have much success until Mr. Sample, Mr. Felder, Mr. Hooper and Mr. Henderson moved to Los Angeles and changed their name to the Jazz Crusaders, a reference to the drummer Art Blakey’s seminal hard-bop ensemble, the Jazz Messengers.
Their first album, “Freedom Sound,” released on the Pacific Jazz label in 1961, sold well, and they recorded prolifically for the rest of the decade, with all four members contributing compositions, while performing to enthusiastic audiences and critical praise.
In the early 1970s, as the audience for jazz declined, the band underwent yet another name change, this one signifying a change in musical direction. Augmenting their sound with electric guitar and electric bass, with Mr. Sample playing mostly electric keyboards, the Jazz Crusaders became the Crusaders.
Their first album under that name, “Crusaders 1,” featuring four compositions by Mr. Sample, was released on the Blue Thumb label in 1972.
With a funkier sound, a new emphasis on danceable rhythms and the addition of pop songs by the Beatles and others to their repertoire, the Crusaders displeased many critics but greatly expanded their audience.
For Mr. Sample, plugging in was not a big step. He had been fascinated by the electric piano since he saw Ray Charles playing one on television in the mid-1950s, and he had owned one since 1963.
Nor did he have any problem crossing musical boundaries: Growing up in Houston he had listened to and enjoyed all kinds of music, including blues and country.
“Unfortunately, in this country, there’s a lot of prejudice against the various forms of music,” Mr. Sample told The Los Angeles Times in 1985. “The jazz people hate the blues, the blues people hate rock, and the rock people hate jazz. But how can anyone hate music? We tend to not hate any form of music, so we blend it all together. And consequently, we’re always finding ourselves in big trouble with everybody.”
They didn’t find themselves in much trouble with the record-buying public. The Crusaders had numerous hit albums and one Top 40 single, “Street Life,” which reached No. 36 on the Billboard pop chart in 1979. Mr. Sample wrote the music and Will Jennings wrote the lyrics, which were sung by Randy Crawford.
By the time “Street Life” was recorded, Mr. Henderson had left the Crusaders to pursue a career as a producer. Mr. Hooper left in 1983. Mr. Sample and Mr. Felder continued to work together for a while, but by the late 1980s Mr. Sample was focusing on his solo career, which had begun with the 1969 trio album “Fancy Dance” and included mellow pop-jazz records like “Carmel” (1979).
His later albums included the unaccompanied “Soul Shadows” (2004). His last album, “Children of the Sun,” is to be released this fall.
He also maintained a busy career as a studio musician. Among the albums on which his keyboard work can be heard are Marvin Gaye’s “What’s Going On,” Joni Mitchell’s “Court and Spark” and “The Hissing of Summer Lawns,” Tina Turner’s “Private Dancer,” Steely Dan’s “Aja” and “Gaucho,” and several recordings by B. B. King.
His music has been sampled on numerous hip-hop records, most notably Tupac Shakur’s “Dear Mama.”
Joseph Leslie Sample was born on Feb. 1, 1939, in Houston, the fourth of five siblings, and began playing piano when he was 5.
His survivors include his wife, Yolanda; his son, Nicklas, a jazz bassist with whom he occasionally performed; three stepsons, Jamerson III, Justin and Jordan Berry; six grandchildren; and a sister, Julia Goolsby.
Mr. Sample’s fellow Crusader Mr. Henderson died in April.
In recent years, Mr. Sample had worked with a reunited version of the Crusaders and led an ensemble called the Creole Joe Band, whose music was steeped in the lively Louisiana style known as zydeco. At his death he had been collaborating with Jonatha Brooke and Marc Mantell on a musical, “Quadroon,” which had a reading in July at the Ensemble Theater in Houston.
Correction: September 18, 2014
An obituary on Monday about the pianist Joe Sample misstated the year his album “Soul Shadows” was released. It was 2004, not 2008.
Emma G. Fitzsimmons contributed reporting.
A version of this article appears in print on September 15, 2014, on page D10 of the New York edition with the headline: Joe Sample, 75, Crusaders Pianist, Dies. Order Reprints|Today's Paper|Subscribe