William Hart, Driving Force Behind the Delfonics, Dies at 77

William Hart, who as the lead singer and chief lyricist of the soul trio the Delfonics helped pioneer the romantic lyrics, falsetto vocals and velvety string arrangements that defined the Philadelphia sound of the 1960s and ’70s, died on July 14 in Philadelphia. He was 77.

His son Hadi said the death, at Temple University Hospital, was caused by complications during surgery.

The Delfonics combined the harmonies of doo-wop, the sweep of orchestral pop and the crispness of funk to churn out a string of hits, 20 of which reached the Billboard Hot 100. (Two made the Top 10.)

Almost all of them were written by Mr. Hart in conjunction with the producer Thom Bell, including “La-La (Means I Love You),” “I’m Sorry” and “Ready or Not Here I Come (Can’t Hide From Love),” all released in 1968, and, a year later, “Didn’t I (Blow Your Mind This Time),” which won a Grammy for best R&B vocal by a duo or group.

Alongside Motown in Detroit and Stax in Memphis, the Philadelphia sound was a pillar of soul and R&B music in the 1960s and ’70s. More relaxed than Motown and less edgy than Stax, it drew on both the doo-wop wave of the late 1950s — especially groups like Frankie Lymon and the Teenagers and Little Anthony and the Imperials — and a slowed-down version of the funk perfected by James Brown.

Mr. Hart looked to all those artists, along with songwriters like Burt Bacharach and Hal David, as inspiration. He preferred to write lyrics after the melodies were in place, working around the strictures they imposed to weave stories about heartbreak, jealousy and old-fashioned romance.

“I could imagine at a very early age what a broken heart was all about,” he told The Guardian in 2007. “Being a young man, I had to put myself in that position. And I found I could just write about it. It’s like imagining what it’s like to jump off a cliff — you can write about it, but you don’t have to actually jump off that cliff.”

In Philadelphia, the Delfonics became mainstays of the frequent “battles of the bands” held at the Uptown Theater, the white-hot center of the city’s soul scene, going toe to toe in satin lapels to see who could be the night’s smoothest crooners.

Their reach went far beyond 1960s Philadelphia. Mr. Hart’s songs have a timeless, dreamy quality, at once emotion-laden and urbane. That’s one reason they have had second and third lives: Singers have remade them, rappers have sampled them, and filmmakers have featured them on soundtracks.

The New Kids on the Block remade “Didn’t I (Blow Your Mind This Time)” in 1989, taking it to No. 8 on the Billboard pop chart. Prince covered “La-La (Means I Love You)” in 1996, the same year the Fugees released a reinterpreted version of “Ready or Not Here I Come (Can’t Hide From Love),” titled simply “Ready or Not.”

The next year the Delfonics and Mr. Hart experienced an even bigger resurgence when Quentin Tarantino featured “La-La (Means I Love You)” and “Didn’t I (Blow Your Mind This Time)” on the soundtrack of his film “Jackie Brown” and as a plot point, using the songs’ smooth, nostalgic sound to draw together characters played by Pam Grier and Robert Forster.

“I think the fact that our music is clean helps us make the crossover into the next generation,” Mr. Hart told The Philadelphia Tribune in 2008. “We sing songs that everyone of every age can enjoy. I write most of the songs, and that’s one thing I’ve always tried to do.”

William Alexander Hart was born on Jan. 17, 1945, in Washington and moved with his family to Philadelphia when he was a few months old. His father, Wilson, worked in a factory, and his mother, Iretha (Battle) Hart, was a homemaker.

His father gave him the nickname Poogie, which stuck with him long into adulthood.

Along with his son, he is survived by his wife, Pamela; his brothers, Wilbert and Hurt; his sisters, Niecy and Peaches; his sons, William Jr., Yusuf and Champ; 11 grandchildren; and two great-grandchildren.

William began writing songs when he was about 11 and immediately latched onto the themes of love lost and regained that would dominate his lyrics for decades.

He joined his brother Wilbert and a friend from high school, Randy Cain, in a group they at first called the Orphonics, a variation on “aurophonic,” a term William saw on a stereo box. They tweaked the name to Delfonics at the suggestion of their manager, Stan Watson.

Mr. Hart was still working a day job in a barbershop when a friend put him in touch with Mr. Bell, who was already well known around Philadelphia for the lush, sensual arrangements he had done for a local label.

They became a hit-making duo, the Lennon and McCartney of West Philadelphia: Mr. Bell wrote the music and Mr. Hart supplied the lyrics, often almost simultaneously. Mr. Hart claimed they wrote “Didn’t I (Blow Your Mind This Time)” in two hours.

The original Delfonics split up in 1975, but Mr. Hart continued to perform under the name, with lineups that might or might not include members of the original group. Wilbert Hart went on to tour with his own Delfonics, even after his brother won an injunction against him in 2000.

In 2002 Wilbert Hart and Mr. Cain successfully sued William Hart for back royalties. The courtroom clash didn’t prevent the three of them from occasionally reuniting, at least until Mr. Cain’s death in 2009.

Mr. Hart continued to tour using the Delfonics name, his falsetto a bit weaker but his presence still commanding. He also released a number of side projects, including “Adrian Younge Presents the Delfonics” (2013), with Mr. Younge producing and Mr. Hart singing and sliding effortlessly back into the lyricist’s chair.

“It’s like a blank canvas,” he said in a 2013 interview for the music magazine Wax Poetics. “I’m an artist; just give me the canvas, and I’ll paint the painting.”