Attorney General Josh Shapiro has a preferred running mate in his bid to be Pennsylvania’s governor.

Shapiro on Tuesday plans to endorse state Rep. Austin Davis, a Western Pennsylvania Democrat who will simultaneously launch his campaign for lieutenant governor.

The endorsement would break with a recent tradition of Democratic gubernatorial candidates staying out of the lieutenant primary. And it stirred pushback from supporters of another hopeful in the race, Philadelphia state Rep. Brian Sims, who announced his candidacy nearly a year ago.

Davis, a first-term representative from the Mon Valley, an industrial center near Pittsburgh, will announce his run alongside Shapiro in McKeesport on Tuesday morning, both confirmed. The pair will make a second joint appearance in Philadelphia on Wednesday at the Octavius Catto statue outside City Hall.

In an interview Monday, Davis, the first Black representative elected for his district, said his working-class background will benefit the ticket and the office.

“As the son of a Port Authority bus driver and a hairdresser in Allegheny … a first-generation college graduate, with the student loans to prove it … when I talk about working-class families that’s because I’m talking about my family,” he said.

Pennsylvania is one of just a handful of states where candidates for lieutenant governor run separately from candidates for governor in the primary. The winners share their party’s ticket in the general election.

Shapiro told The Inquirer he chose Davis because “I wanted someone who brings a different life experience, who is diverse, who comes from a different part of the state than I do.” He said with Davis as his second-in-command, “there will always be a voice in the room that adds to the conversation and helps us achieve more for the good people of Pennsylvania.”

Since Shapiro has effectively cleared the Democratic field for governor, the endorsement is likely to have a lot of sway. The Shapiro and Davis campaigns will work in tandem; without his own primary challenger, Shapiro can dedicate more time and resources to helping Davis.

Democrats vying for governor have traditionally stayed out of the race for lieutenant governor, resulting in some odd couplings. Former Lt. Gov. Mike Stack ran afoul of Gov. Tom Wolf, who didn’t endorse him when he ran for reelection.

Former Gov. Ed Rendell said Monday that he thinks gubernatorial candidates should get to select their lieutenants, similar to presidential tickets. He said not having that option has hurt some in the past.

Swaying who becomes lieutenant governor also helps Democrats avoid a situation with too many candidates from one part of the state, or without any racial diversity, Rendell said.

“Given the increasingly important role African Americans have played, it would be good to have an African American candidate in one of those three positions of governor, lieutenant governor, senator,” he said.

Davis would be the state’s first Black lieutenant governor. Sims would be the first person to hold the position who is openly gay.

While the duties of lieutenant governor are limited, it’s a role that comes with a spotlight and often sets candidates up to run for higher offices. Lt. Gov. John Fetterman went from a small-town mayor to lieutenant governor to his current position as a front-runner in the Democratic Senate primary.

Davis, 32, worked in county government before running for state representative. Elected in 2018, he also chairs the Allegheny County House Democratic Delegation and is a member of the Pennsylvania Legislative Black Caucus.

Pennsylvania’s Democratic establishment, already lined up behind Shapiro, is largely lining up behind Davis. The campaign said he’s backed by Wolf, Rendell, state House and Senate leadership, and the majority of the House Democratic caucus, along with Mayor Ed Gainey in Pittsburgh and Philadelphia Council President Darrell Clarke.

Shapiro and Davis have collaborated in recent years, including on an antiviolence initiative in McKeesport and on a police misconduct database set up by the AG’s office in the wake of George Floyd’s killing.

Shapiro had a short list of lieutenant governor candidates, which included Sims and Rep. Patty Kim, of Harrisburg, who decided not to run.

Sims said in a statement after the endorsement that Democrats “are lucky to have a historically diverse field of candidates to choose from.”

Sims, first elected in 2012, has raised at least $285,000 in his bid and enters the race with a profile and some name recognition, though he’s also been the subject of some controversy, including in 2019 when he yelled at teenage protesters at Planned Parenthood.

Some of Sims’ backers were critical of Shapiro’s decision to inject himself into the race.

Amanda Waldman, a Democratic statehouse candidate in Lycoming County, called it a “hijacking.”

“If the powers that be, the upper echelon of the political world, is making a decision on who a candidate should be in spite of what the constitution says specifically about the lieutenant governor’s race, what’s the point of turning out?” she asked.

Waldman said she has nothing against Davis but is wary of a candidate who announces his run in the same moment he’s endorsed by Shapiro.

“It feels very forced...,” she said. “Why hasn’t he been out doing the work? And why is Shapiro’s campaign doing it for him?”

There are ongoing efforts in the Pennsylvania legislature to change the constitution so that nominees for lieutenant governor do not run in separate primaries. None are likely to take effect in time to influence the May 2022 primary.

Davis said while the early “ticketing up” may be unique for Democrats in recent elections, he thinks it makes sense in a year where the gubernatorial front-runner is thus far unopposed. He said voters appreciated decisive leaders.

“We know we want Josh Shapiro to lead us as our governor and he wants a strong governing partner in myself, and, while it’s unique, it’s what voters are looking for,” Davis said.

Staff writer Chris Brennan contributed to this article.