Mayor Byron W. Brown has selected an 18-year veteran of City Hall to become his top finance aide.

Brown is seeking Common Council approval to appoint Budget Director Donna J. Estrich as commissioner of administration, finance, policy and urban affairs.

“She’s steady, she knows the budget better than anybody else,” said Deputy Mayor Steven M. Casey. “Everyone in the building knows Donna to be fair, honest and works very hard.”

If confirmed, Estrich will succeed Janet E. Penksa, who resigned earlier this month. The commissioner oversees 20 to 30 people and holds one of the more high-profile positions in City Hall.

The post is a key part Brown’s Cabinet and takes part in the CitiStat panel, in which top staff question department heads in televised meetings.

Common Council President Richard A. Fontana said Estrich is capable, and he expects the Council to approve her appointment. “I think she’ll be an excellent commissioner,” Fontana said. “I have no reservations.”

He said Council members will likely ask Estrich questions during the Legislation Committee meeting Jan. 2 before they vote on the appointment, which requires a simple majority. A vote will likely be held during the Jan. 8 Council meeting.

Estrich has been the city budget director since 2006. Earlier that year, she was interim commissioner of administration and finance following longtime Finance Commissioner James B. Milroy’s resignation and before Penksa was appointed.

She has also worked as a management and budget analyst.

People in City Hall said Estrich can be relied upon to be forthright about the city’s finances. “Donna knows municipal finance like the back of her hand,” said Majority Leader Demone A. Smith.

Smith said a national search wasn’t necessary and that it would be hard to find anyone to say anything negative about her.

Casey said Estrich would be paid the budgeted salary of $119,239 annually, which is the highest salary in city government.

Estrich holds a bachelor’s degree from Buffalo State College and is pursuing a master’s in public administration.

She will maintain her seat on the city’s Water Board.

If the Council confirms the appointment, the city will look for another budget director, Casey said.

Penksa left City Hall this month to be executive director of the Jacobs Institute at the Buffalo Niagara Medical Campus.