League sources told NFL Network that Ingram agreed to a one-year contract with the Steelers. The team has yet to confirm the agreement.
The 32-year-old Ingram fills a significant gap in the Steelers' defense left by the departure of Bud Dupree, who signed with the Tennessee Titans earlier this year in free agency.
"I met with [Steelers] coach [Mike] Tomlin. You can tell he's very involved and a players' coach," Ingram told NFL Media. "That's what stood out to me. He wants to win, and that is what I am on.
"My role is my role. He just told me to come in and be me. Everyone knows how I play."
Ingram, who received interest from other clubs and visited with the Steelers on Monday, will compete for the spot opposite star edge rusher T.J. Watt that is currently held by second-year outside linebacker Alex Highsmith.
The Los Angeles Chargers selected Ingram in the first round of the 2012 draft out of South Carolina. He spent his first nine seasons with the franchise, racking up the fourth-most sacks (49) in team history.
Ingram, a three-time Pro Bowl selection from 2017-19, played in just seven games last season due to a nagging knee injury that caused him to land on injured reserve twice. He failed to record a sack in 2020 for the first time in his career.
The Chargers declined to re-sign him after his four-year, $64 million deal expired after the 2020 campaign.