Evans -- representing Ward 2, which stretches from Georgetown into downtown and the Shaw neighborhood -- has said since last fall that he would run for chairman if Gray made the decision to give up the job to challenge Mayor Adrian Fenty.
A spokesman for Brown, an at-large member of the council, said Wednesday that he will run against Evans. He joined the council in 2005 and chairs the committee on economic development.
Evans currently is the longest serving council member, having won a special election to replace the late John A. Wilson in 1990. Evans also is chairman of the influential Finance and Revenue Committee.
Evans is seen as a council ally of the mayor and could benefit from Fenty's campaign field operations. Evans also is a prolific fundraiser and is expected to have no problem in that area. He is a pro-business member of the council who also pays close attention to community needs in his ward.
Evans is less well-known citywide despite a run for mayor in 1998 -- a race that was won by Anthony Williams.
Neither Evans nor Brown has to give up their Council seats to run for chairman.