When he turned 70 a couple of years ago, Richie Havens noted with pride that, "I don't feel one iota different from the day I walked into Greenwich Village" 50 years prior. "Everything I hoped for has happened," he told Billboard. "I never had a bad day on stage. I don't think I'm ever going to go away...least while I'm alive."

Havens, a protest music hero ("Handsome Johnny," "No Opportunity Necessary...," "Stop Pulling and Pushing Me") and the man who opened the 1969 Woodstock festival, died on Monday morning from a sudden heart attack at his home in New Jersey, according to his publicist. He was 72. In March of 2012, Havens had announced an end to his 45-year touring career, citing health issues.

Born in Brooklyn, Havens started out singing doo-wop and gospel -- which inspired him to write songs, but not necessarily in those genres. "I said to myself when I started singing doo-wop that I would never write another song like those guys were writing," he explains. "They were fantastic writers, which is what educated me. I lot of guys went off to do their own doo-wop stuff, But I wanted to figure another way around and do something that was different and new and my own."

The search led Havens to "the melting pot of poetry" that was New York's Greenwich Village during the 50s and 60s. Arriving when he was 20 years old, he was mentored by Fred Neil -- "He didn't know I was singing with a doo-wop group in Brooklyn, but he knew something in his music had changed me," Havens recalled -- and put out a pair of albums for Douglas Records before Bob Dylan's manager Albert Grossman signed him and got him a deal with Verve Forecast. "Mixed Bag" in 1967 featured "Handsome Johnny," which Havens co-wrote with actor Louis Gossett Jr., and a cover of Dylan's "Just Like a Woman."

Havens mixed a variety of styles into his music, drawing on folk, blues, rock, jazz, funk and even elements of country and bluegrass that filtered through the scene in New York. He was also an avid interpreter of other songwriters' including Dylan, John Lennon and Paul McCartney, and Leonard Cohen. It made it hard for him to find a niche but easy to find places to play; he laughingly remembered that his first who out of town, in Detroit, was at a jazz club, and the next, in Chicago, was at a blues spot.

I didn't know what I did -- I just did it and didn't call it anything except music.

"I looked at the poster for that first show and it said, 'Richie Havens -- folk/jazz singer.' I went, 'Really? Is that what I am? Is that what I do?' I just went into any situation the put me in, and people seemed to like it."

Havens' breakthrough situation was at Woodstock, of course. Pressed by organizers to open the show when another artists' equipment was stuck on the New York Thruway, Havens -- who was originally scheduled to go on fifth -- played a galvanizing set that included a vamp on "Motherless Child" that morphed into his song "Freedom."

"It was 5 o'clock and nothing was happening yet," Havens remembered. "I had the least instruments and the least people (in his band). But they had to catch me first. I felt like, 'They're gonna kill me if I go up on stage first. Give me break. I need those four people in front of me to warm up the crowd.' But the people were great. I was supposed to sing 40 minutes, which I did, and from the side of the stage they go, 'Richie, four more songs?' I went back and did that, then it was, 'Four more songs...' and that kept happening 'til two hours and 45 minutes later I had sung every song I know."

Woodstock gave Havens a boost to his highest-charting albums -- "Richard P. Havens, 1983" in 1969 (No. 80 on the Billboard 200) and "Alarm Clock" in 1971 (No. 29). The latter featured his lone Billboard Hot 100 single, a cover of the Beatles' "Here Comes the Sun" that peaked at No. 16. Havens' final chart entry was the 1987 album "Simple Things," which reached No. 173, while his final set of original material was 2008's "Nobody Left to Crown."

Notable moments in Havens' career included television performances on "The Ed Sullivan Show" and "The Tonight Show," a role in the 1972 stage production of The Who's "Tommy," a roles in the films "Catch My Soul," "Greased Lightning," Bob Dylan's "Hearts of Fire" and Todd Haynes' Bob Dylan-inspired film "I'm Not There," singing "Tombstone Blues." During the mid-70s he co-founded the Northwind Undersea Institute, a children's-oriented museum in the Bronx, as well as the Natural Guard, an organization to teach children about ecological issues.

He sang at President Bill Clinton's inauguration in January of 1993, and a decade later he received the American Eagle Award form the National Music Council. He collaborated with the electronic duo Groove Armada on "Hands in Time" for the "Collateral" film soundtrack, and he's worked with Genesis members Peter Gabriel and Steve Hackett, blues artist Bill Perry and with David Letterman CBS Orchestra drummer Anton Fig. Havens published an autobiography, "They Can't Hide Us Anymore," in 2000 and was inducted into the Long Island Music Hall of Fame in 2006.

Havens is survived by three daughters, five grandchildren and two great-grandchildren. Through his publicist, Haven's family has asked "for privacy during this difficult time" but promised that "a public memorial will be planned for a later date."