Prince George’s County Executive Rushern L. Baker III on Tuesday named Robin Barnes-Shell, 51, a lawyer with a long history of public service, to lead a newly created ethics office that Baker formed to help weed out corruption.

As acting executive director of the Office of Ethics and Accountability, Barnes-Shell, who had worked in various roles in the county school system, is tasked with investigating possibly unethical conduct or illegal acts in county government. The ethics office, with a budget of about $350,000, will also administer an anonymous tip line and will be responsible for training the county’s 6,000 employees in ethical practices.

The nomination is subject to approval by the County Council.

Baker, who campaigned on running a cleaner, more transparent government, took office just a few weeks after his predecessor, Jack B. Johnson (D), was arrested on corruption and bribery charges.

Johnson’s wife, then-incoming council member Leslie Johnson (D-Mitchellville), was also arrested in November 2010. She was taken into custody after she was overheard on a FBI wiretap discussing with Johnson how she should hide $79,600 in cash in her underwear.

In early 2011, as one of his first initiatives in office, Baker brought together an ethics review panel that offered a reform plan, including employee training on ethics, the creation of the anonymous tip hotline and expanded protections for whistleblowers.

Baker had hoped to institute an independent inspector general, but he abandoned that idea. He secured the County Council’s support to expand the county’s ethics office, advancing his ethics reform effort.

In a statement, Baker cited Barnes-Shell’s experience starting up new offices and establishing procedures in the public sector. He said she would be able “to build a concept or idea into a reality.”

“I am confident that she will create an effective and efficient office that will ensure our government and its employees are held to the highest ethical standards of conduct and accountability,” Baker said.

Barnes-Shell previously worked in the Prince George’s school system, for which she developed processes to provide accountability and address constituent concerns. She also worked in the office that provides oversight of student disciplinary hearings, and she served as a hearing officer for employee disciplinary appeals. Her salary is $130,000.

In an interview, Barnes-Shell described the office’s purpose as ensuring “transparency and accountability” in the county. “The first thing is to get the office up and running,” she said.

Barnes-Shell is a graduate of Georgetown University Law Center. She lives in Glenn Dale with her husband and five children.