Fisher is being challenged in the May 5 primary by Toledo businessman Bruce Douglas, who last week selected Mark Hatch, a Columbus school board member, as his running mate.
Secretary of State Bob Taft, who is unopposed in the Republican primary, will likely announce his running mate before the end of the week. The filing deadline for candidates is Feb. 19.
Coleman, 42, has served on the Columbus City Council since 1992 and has been its president for a year. A native of Toledo, he is a graduate of the University of Cincinnati and received his law degree from the University of Dayton in 1980.
Fisher, 46, said Coleman brings a variety of talents to the campaign and is well-versed in urban problems. "His experience as a city councilman and his proven talents as a problem solver will be a tremendous asset to the state," Fisher said.
At his news conference, Fisher continued to sidestep questions about the school funding legislation that has been stalled in the General Assembly. Neither he nor Taft will comment directly on whether the legislature should raise taxes to help pay for school improvements and a new funding formula ordered by the state Supreme Court.
"I'm not going to oppose or come out for any one plan," Fisher said.
Douglas has developed his own school funding plan that calls for a 1 1/2 -cent increase in the state sales tax to pay for school improvements.
Fisher said he does not plan to directly criticize Douglas during the campaign, but said, "I do not think we should have a $2 billion tax increase on working families as he's proposed."
Douglas' proposal would raise far less than $2 billion in new taxes because it includes a 20 percent reduction in property taxes, along with some business tax reductions.