In a sweeping change of the guard aimed at reversing its declining fortunes, Warner Bros. Records has installed a new executive team led by Rob Cavallo, previously Warner Music Group chief creative officer, who will take over as chairman.

As part of the restructuring, former WBR chairman-CEO Tom Whalley and chief operating officer/Reprise Records prexy Diarmuid Quinn are ankling.

Whalley had honed his skills as an A&R exec, and WBR will now move on with another talent-savvy exec at the top.

Cavallo, who originally worked at the label in 1987 as an A&R rep, went on to become senior VP of A&R at Warner/Reprise and a top producer of multiplatinum albums like Green Day’s “American Idiot.” He was appointed chief creative officer at WMG last year (Daily Variety, Oct. 8).

Todd Moscowitz (previously exec veep of WBR, chief exec of WMG’s Independent Label Group and prexy of Asylum Records) has been named co-president and chief exec of WBR. Before joining the label in 2009, Moscowitz was general manager of Def Jam Records, head of Rush Communications and a partner at Violator Management.

Livia Tortella (formerly exec VP-g.m. of WMG’s Atlantic Records) has been elevated to co-president-COO. A long-term exec in the Polygram family, she joined Atlantic Records in 2004. She engineered the launch of Atlantic’s deal with Chop Shop Records, home of the bestselling “Twilight” soundtrack albums.

Moscowitz and Tortella are both considered close associates of Lyor Cohen, WMG vice chairman and chairman-CEO, recorded music — Americas and the U.K.

Cohen said in a statement: “The new Warner Bros. executive team represents the ideal combination of skills to operate a successful music company in today’s radically evolving industry environment.”

Once considered the Cadillac of record labels and a developer of long-term careers, WBR has struggled to find its footing in recent years and of late has been eclipsed as a sales power within WMG by the Atlantic Records Group.

Parent WMG ranks third among the four major labels in sales, and observers continue to speculate that a merger between it and fiscally troubled No. 4 major EMI Music is inevitable.

Ironically, changes at the apex of WBR followed the label’s best week in some time, as a trio of its acts entered the top 10 of the national album chart: Disturbed (No. 1), Lyfe Jennings (No. 6) and the Goo Goo Dolls (No. 7), the Buffalo, N.Y., band signed by Cavallo in the ’80s.

It has been a sluggish year for the Burbank-based label, with new albums by Avenged Sevenfold, Gucci Mane, Tom Petty & the Heartbreakers and Jason Derulo and ongoing sales from Muse and Michael Buble providing some of the few bright spots. Top-selling hard rock unit Linkin Park’s “A Thousand Suns” arrived in stores Tuesday.

Overall, WMG’s recorded music business declined 17.9% in the quarter ended June 30 vs. a year earlier.

Exiting chairman Whalley joined Warner Bros. in 2001 from Universal Music Group’s Interscope Geffen A&M division, where he was president. He began his career in 1979 in the Warner Bros. mailroom and rose to A&R exec at the label before moving to Capitol Records in the ’80s. In 1990, Whalley became a founding member of the Interscope Records staff.

Despite reports of ongoing friction between Whalley and Cohen since the latter’s arrival at WMG from UMG’s Island Def Jam Music Group in 2004, both men were publicly gracious as Whalley’s departure was announced.

In a statement, Whalley thanked Cohen and WMG chairman-CEO Edgar Bronfman Jr., adding, “I leave (Warner Bros.)extremely proud of what we’ve accomplished.”

Cohen called Whalley “one of this industry’s top executives,” and added, “Tom embodies a rare combination of great creative instincts with a deep understanding of the music business, and we are privileged to have had him lead Warner Bros.”

Changes in the exec suite preface end of WMG’s fiscal year on Sept. 30. Company’s stock closed at $4.99 (down 0.40%) in Tuesday trading on the New York Stock Exchange.