ATLANTA — Former Atlanta Mayor Kasim Reed filed paperwork Wednesday to run again for his old job just four years after leaving City Hall.

A document Reed’s campaign team filed with the Georgia ethics commission opens the door for Reed to start accepting political contributions for the 2021 race. He jumped in one month after current Mayor Keisha Lance Bottoms announced she won’t seek reelection to a second term.

The president of the Atlanta City Council, Felicia Moore, also is running, having announced her candidacy before Bottoms left the race. Two other council members, Antonio Brown and Andre Dickens, also launched campaigns.

Some political observers had expected Reed to seek a comeback. He was elected mayor in 2009 at age 40 after serving in the Georgia legislature. He spent two terms in the mayor’s office, leaving at the end of 2017 as his administration was dogged by a federal investigation into city contracts and finances.

Reed’s campaign paperwork comes as the former mayor plans to celebrate his 52nd birthday with a fundraising party Thursday. The Atlanta Journal-Constitution reported it obtained an invitation that spelled out donor levels from $25,000 for hosts and $1,000 for guests.

Bottoms is the first Atlanta mayor since World War II to decide against seeking a second term. Her political profile rose in 2016 when she was among the women President Joe Biden considered as a potential running mate.