Vice President Kamala Harris laid out a broad vision of her economic plan on Wednesday as she sought to bridge the political divide between the progressive senator who ran for president in 2019 and the pragmatic, pro-business candidate she is presenting herself as now.

During a speech in Pittsburgh in which she declared “I am a capitalist,” Ms. Harris promised to protect and expand U.S. manufacturing as she tried to convince voters that she will defend and lift up the middle class.

“From our earliest days, America’s economic strength has been tied to our industrial strength,” she said. “The same is true today. So I will recommit the nation to global leadership in the sectors that will define the next century.”

Speaking not with the trappings of a raucous campaign rally but in front of the sober signage of the Economic Club of Pittsburgh, Ms. Harris delivered remarks seemingly tailored to voters sitting in wood-paneled offices reading the print edition of The Wall Street Journal. Such voters may have supported John McCain and Mitt Romney, and might believe the economy was better four years ago, but the Harris campaign appears to be hoping that many will now have trouble stomaching the idea of voting for former President Donald J. Trump.

Ms. Harris revealed little new about her economic plans in her 39-minute speech, but she reiterated many of the populist themes of her economic agenda. She promised tax increases on the largest corporations while pledging tax breaks for small businesses and homebuilders.

She also pledged to invest in what she described as some of the most promising industries of the 21st century: bio-manufacturing, aerospace, artificial intelligence, blockchain technology and clean energy.