A 14-year member of the council who chaired the key budget and public safety committees, Young, 55, fills the seat vacated by Stephanie C. Rawlings-Blake, who was sworn in as mayor after Sheila Dixon's resignation last week.
"I will never forget that I work for you, the citizens of Baltimore," Young said. "I look forward to us rolling up our sleeves and getting work done that is in the best interest of our city."
Young, known for his fiery personality and blunt pronouncements, is the highest-ranking city leader in at least a decade to hail from the east side and has close ties with many influential East Baltimore leaders, including former Councilman Carl Stokes and state Sen. Nathaniel J. McFadden.
Councilwoman Helen Holton praised Young's commitment to "the rights of citizens, particularly those that are less advantaged, that need a voice and advocate."
The fifth of 10 children born to a forklift driver and a homemaker, Young prides himself on being attuned to the needs of the city's poorest residents. Several of his siblings, his wife and daughters, and other relatives packed into the council chambers for Monday's meeting and cheered loudly for the new president.
Young has pledged to resign his position with the state human resources department upon becoming council president.
In one of his first acts as president, Young reconfigured several council committees. Councilwoman Belinda K. Conaway will replace him as budget committee chair, and Councilman James B. Kraft, a close ally, will succeed him as public safety chair.
Councilman William H. Cole IV, who had challenged Young for the president's seat before withdrawing last week, lost his place on the land use and education committees. Young named Councilman Bill Henry to replace Cole as vice chair of the taxation and finance committee.
Although the mayor's staffers denied endorsing a candidate for president, many council members said Rawlings-Blake's administration was privately rallying votes for Cole.
Cole, who is recovering from shoulder surgery, congratulated Young at Monday's meeting. Motioning to his arm in a sling, he said, "There's been a lot of talking about arm-twisting. ... I think I lost."
After the council vote, Rawlings-Blake administered the oath of office to Young in the mayor's ceremonial chamber, the same room where she was sworn in last week.
The mayor told the new president to repeat the oath after her, but as soon as she said, "I," Young jumped ahead and stated his name.
The mayor paused and smiled at Young. "We'll figure this out together," she said.