Speaking at an afternoon news conference in his office at City Hall, Dellums said Edgerly's retirement "is not a reaction" to recent news reports about Edgerly.
Dellums said he and Edgerly agreed on Jan. 28 that she would retire effective July 31 and they decided to make the announcement public today.
Joining Dellums at the news conference, Edgerly smiled broadly at the large group of reporters who gathered in the mayor's office and said, "I'm amazed at how much star power I have."
Edgerly said she's deciding to retire now because her family members have been trying to get her to retire for many years.
Edgerly said that despite reports that Dellums recently asked the city's department heads to report to him instead of her, "I am the city administrator with all the duties and responsibilities" of the office.
After Dellums and Edgerly made brief remarks, they left Dellums' office and refused to take questions.
The Oakland Police Department on June 17 said that a three-month investigation called "Operation Nutcracker" resulted in the arrest of 54 members of the Acorn gang, including Edgerly's nephew, reputed gang member William Lovan, a 27-year-old meter repairman for the city of Oakland.
Reports surfaced last week that Edgerly allegedly attempted to interfere with Oakland police about 10:30 p.m. on June 7 when they towed Lovan's car from a spot next to a West Oakland liquor store because he allegedly had a gun inside.