Powell died Monday night at his home near San Diego. The San Diego Union-Tribune reported that Powell had been dealing with heart and other health problems and had recently spent a week in the hospital.
The Raiders said in a statement that Powell's "strong convictions and athletic prowess helped shape the pro football landscape of the 1960s."
Powell, 6 feet 3 and 211 pounds, played 10 years in the NFL and AFL for the Eagles, Titans, Raiders, Bills and Vikings. He led the AFL with 1,130 yards receiving in 1962 for the Titans before joining the Raiders the following season.
He had his best success in Oakland, leading the AFL with 1,301 yards and 16 touchdown catches in 1963 in Al Davis' first year as coach. Powell had 1,361 yards receiving the next season.
He ended his career with 479 catches for 8,046 yards and 81 touchdowns. He was a first-team All-Pro in 1960 and 1963 and made four Pro Bowls.
Powell came from a family of athletes. He was born Feb. 25, 1937, in Dallas. His father, a standout in tennis, golf and baseball, and mother moved to San Diego to raise their large family.
Powell was a star basketball and football player at San Diego City College and San Jose State. He played the 1959 season in the NFL with Philadelphia but left the team after refusing to stay in separate quarters from white players during an exhibition in Norfolk, Va.
"The challenges that were before me were social challenges," Powell told the Contra Costa Times in 2007. "I chose to challenge 'em while others chose not to. ... I made a lot of people angry."
Powell's older brother, Charlie, who played in the NFL and boxed against Muhammad Ali when Ali was known as Cassius Clay, died last year.