"Over the past 10 years, P&G's total return to shareholders is less than half that of its peers and it has been in the bottom quartile over most recent time frames," Trian said in its statement. "Trian believes P&G needs to address the root causes of this consistent underperformance, including deteriorating market share across most of its categories and excessive cost and bureaucracy."
Peltz has said he's looking to ensure greater "management accountability" at P&G, where he wants to "accelerate positive change." However, Trian hasn't detailed any specific plans of attack nor strategies to achieve said results.
By Thursday afternoon, P&G CEO David Taylor called Peltz out on this.
"I want to prevent anything from derailing the work we're doing," Taylor told CNBC. "The fact that he has good advice doesn't mean we just add him to the board."
P&G's plan to please Wall Street has been to trim unprofitable brands from its portfolio, and to cut as much as $10 billion in costs from the business over the next five years.
"We went from 16 categories down to 10... 170 brands down to 65," Jon Moeller, Procter & Gamble CFO, said on CNBC's "Squawk Box" Thursday morning, discussing the latest quarter. He said P&G is seeing progress and that the company is focused on improving into 2018.
"I truly believe the best days of our company and [for] the consumer-products space are ahead of us," Moeller said. "We are in the middle of the biggest transformation ever as a company."
In the latest quarter, Cincinnati-based P&G managed to drive costs even lower, which aided in boosting its profit; P&G's net sales remained flat at $16.08 billion, though the company's quarterly profit climbed 13.5 percent.
Selling, general and administrative expenses fell 7 percent in the quarter.
Net income rose to $2.22 billion, or 82 cents a share, from $1.95 billion, or 69 cents per share, one year ago. Excluding restructuring charges and the results from discontinued operations, P&G earned 85 cents, outpacing analysts expectations of 78 cents a share.
The company's total organic sales — which excludes the impact of foreign exchange, mergers and acquisitions — grew 2 percent on a 2 percent increase in organic volume.
"We met or exceeded each of our going-in objectives for fiscal year 2017 in a challenging macro and competitive environment," CEO Taylor said in the earnings release.
"We made significant progress on our key priorities: accelerating organic sales growth, continuing to drive strong productivity improvement and cost savings, strengthening our organization and culture and completing moves to simplify and strengthen our product portfolio."
Bright spots, and thus sales drivers, in P&G's portfolio for the quarter were in beauty and fabric and home care. Both of these segments saw their organic sales climb 5 percent from a year ago. In beauty, P&G said its skin and personal care products grew sales in the high-single digits, aided by more innovation.
P&G's grooming and health-care segments saw their organic sales fall 1 percent from a year ago. Pricing pressure in the shave care and oral care categories is what drove results lower during the quarter, the company said.
Looking ahead, P&G said it expects earnings to grow 5 percent to 7 percent in 2018, also warning that the first quarter of fiscal 2018 will be the "lowest organic sales and core EPS growth period of the year."
Headwinds from "portfolio choices" and the a recent reduction in Gillette prices across the U.S. are the primary reasons for tough first quarter, the company said, but cost savings are still expected to build as 2018 progresses.