Val Arkoosh, chair of the Montgomery County Board of Commissioners, launched her bid for U.S. Senate on Monday, touting her experience as a physician and head of the state’s third-largest county — and one of its most Democratic.

Arkoosh, a Democrat from Springfield Township, has led her county’s response to the coronavirus pandemic, elevating her profile in the Philadelphia region over the last year.

“We are just at a critical time in our country,” Arkoosh, 60, said in an interview. “People are wondering how we’re gonna come out of this pandemic, we have some real issues around systemic racism and we’ve got some long-standing issues that need to be tackled like climate change. And as I talk to Pennsylvanians, they want someone who is going to commit to doing the hard work. I’ve been a problem solver all my life.”

Arkoosh was appointed to fill a vacancy on the board in 2015, a year after an unsuccessful run for Congress. She won a full four-year term later that year and again in 2019. She was unanimously elected chair by her fellow commissioners in 2016.

Arkoosh is the first female chair of Montgomery County’s governing body. If elected to the Senate seat currently held by Republican Sen. Pat Toomey, she would be Pennsylvania’s first female U.S. senator.

Toomey isn’t seeking reelection, setting up one of the most competitive races in the country — one that could determine control of the Senate and the fate of President Joe Biden’s legislative agenda in the final two years of his term.

Arkoosh is the third major Democratic candidate in a field that already includes Lt. Gov. John Fetterman of Allegheny County and State Rep. Malcolm Kenyatta of Philadelphia. Other Democrats widely seen as possible candidates include U.S. Reps. Madeleine Dean of Montgomery County, Chrissy Houlahan of Chester County, and Conor Lamb of Allegheny County, as well as Philadelphia Mayor Jim Kenney and State Sen. Sharif Street of Philadelphia. Street is expected to launch an exploratory committee on Friday.

Lower Merion developer Jeff Bartos is running on the Republican side, and others, including former U.S. Rep. Ryan Costello of Chester County, are considering it.

Arkoosh is the second of three Montgomery County commissioners seeking higher office next year. Republican Commissioner Joe Gale is running for governor.

Her home base in heavily Democratic Montgomery County could be an asset in the primary. Biden won the county of 830,000 with a margin 50% larger than Hillary Clinton’s in 2016 and double President Barack Obama’s in 2012. Montgomery saw the biggest Democratic shift of any county in the state last year.

Arkoosh said Montgomery County — with small cities, suburban areas, and 30,000 acres of farmland — mirrors Pennsylvania. She supports a $15 minimum wage, which Montgomery County instituted for its employees, and supports ending the filibuster.

“I’ve had to serve all of those different constituents so I feel ready and able to take that experience … all across the state,” she said. “Certainly there is a very strong Democratic base here in the county and I would hope that most of those individuals would be interested in supporting me in that primary.”

» READ MORE: The 2020 election established Montgomery County as a powerful Democratic stronghold in Pennsylvania

In the competitive 2018 Democratic primary for lieutenant governor, which Fetterman won, Philadelphia and its four collar counties accounted for 41% of all votes.

Arkoosh signaled that she will run on her background as a physician turned public health advocate and educator. As president of the National Physicians Alliance, Arkoosh helped fight for the passage of the Affordable Care Act, Obama’s signature legislative achievement. She is a former chair and program director in the Department of Anesthesiology at the Drexel University College of Medicine, and worked on faculty at the Perelman School of Medicine at the University of Pennsylvania.

“In 23 years in operating and emergency rooms, I’ve seen my share of tragedy,” she said in her launch video. “The trauma of gunshot victims, denials by insurance companies and huge disparities in health care based on race, gender, and income.”

Arkoosh was front and center in the state’s early response to the pandemic when a series of initial cases were reported in Montgomery County. Philadelphia’s suburban counties have more recently butted heads with state officials over vaccine distribution, arguing their region hadn’t received sufficient doses. Last week, the state announced those counties will receive an increased supply of single-shot Johnson & Johnson vaccine doses.

Arkoosh said the pandemic revealed the need for more public health funding. “We hear a lot of discussion about rebuilding infrastructure and one of those things is public health infrastructure,” she said.

She said her work ushering the county through the final months of the pandemic will take first priority over her campaign. “I just want to be very clear, I’ve taken two oaths in my life,” she said. “The first was an oath to be a doctor. The second was a county commissioner, and in both cases I always pledged to put the people I’m serving first.”

Arkoosh lost a four-person 2014 primary to represent what was then Pennsylvania’s 13th Congressional District to Brendan Boyle, who went on to win the seat. Boyle, a Northeast Philadelphia Democrat who had been considering a Senate campaign, said last weekend that he won’t run.

Arkoosh has already tapped some high-profile personnel for her campaign, including pollster Jefrey Pollock and Fiona Conroy, who’s worked on statewide campaigns in Pennsylvania and successfully managed the 2012 reelection campaign of U.S. Sen. Joe Manchin, a West Virginia Democrat. Arkoosh’s communications director Rachel Petri worked on the campaigns of Ohio U.S. Sen. Sherrod Brown and Cal Cunningham’s bid for Senate in North Carolina. Campaign manager Tiernan Donohue worked on U.S. Sen. Mark Kelly’s campaign in Arizona.

Staff writer Andrew Seidman contributed to this article.