Mr. Hart and Mr. Mould met in a record store in 1978 and soon began to play together, along with Mr. Norton, whom Mr. Mould had known previously. The group bonded over their love of significant punk bands of the decade, including the Ramones and the Sex Pistols.
Though Mr. Hart was bisexual and Mr. Mould was gay, their sexual orientation was not a major part of the band’s identity.
“Really, it didn’t define much about the band,” Mr. Hart told the website The A.V. Club in 2000. “If anything, it would have been just another question mark, because we were so unlike the stereotype du jour.”
Mr. Hart and Mr. Mould, both independent-minded musicians, frequently clashed over the band’s direction — both were songwriters — and the group’s contentious breakup, late in 1987, came in the wake of substance-abuse accusations.
“I didn’t enjoy playing hardcore,” Mr. Hart said in the A.V. Club interview. “At the time, while I was drummer for Hüsker Dü even though I played other instruments, it was just such a damn boring job for a drummer.”
He said that even as he began to infuse the band’s albums with more of his ideas, Mr. Mould pushed back in what Mr. Hart characterized as a “showdown,” saying that the group would never be an even split in terms of their ideas.
Mr. Mould said in a Facebook post that Mr. Hart’s death was not unexpected, and he acknowledged their occasional differences.
“We (almost) always agreed on how to present our collective work to the world,” Mr. Mould wrote. “When we fought about the details, it was because we both cared.”
Mr. Hart’s contributions as drummer were not as visible as those of Mr. Mould, the more obvious bandleader. But Mr. Hart had plenty of devotees, as evidenced by the song the Washington band the Posies wrote and dedicated to him.
Mr. Hart wrote two songs released as singles from the band’s major-label debut album, “Candy Apple Grey” (1986) — “Sorry Somehow” and “Don’t Want to Know If You Are Lonely” — as well as two of the band’s most beloved tracks on “Zen Arcade”: “Turn on the News” and “Pink Turns to Blue.”
Ken Shipley, an owner of the reissue label the Numero Group, which is releasing a boxed set of early Hüsker Dü material in November, remembered Mr. Hart in a statement as “disarming and masterminding all at once.”