By Andrew Stern

CHICAGO (Reuters) - Chicago Mayor Richard M. Daleysaid Tuesday he will not run for reelection to a seventhterm in February, saying simply that it was the right time forhim to leave.

"In the coming days I know there will be some reflecting onmy time as mayor. Many of you will search what's behind mydecision. It's simple: I've always believed that every person,especially public officials, must understand when it's time tomove on.

"For me, that time is now," Daley, 68, told reporters.

A Democrat who has never sought higher office since beingelected mayor in a special election in 1989, Daley will surpassthe 21-year tenure in office of his famous father, Richard J.Daley, this year.

On a personal level, Daley's wife, Maggie, has been treatedin recent years for cancer that has spread.

Daley, a former state legislator and county prosecutor whowas reared to adopt the political mantle worn by his legendaryfather, said he had been thinking about not running again forseveral months.

"I have given it my all. I have done my best," he said. "Itjust feels right."

After more than two decades in City Hall, Daley leaves along legacy -- though he has also had his share ofdetractors.

"He'll be remembered positively for shepherding Chicagothrough the transformation from a manufacturing and serviceeconomy to becoming a global city," said political analyst DickSimpson of the University of Illinois at Chicago.

Daley viewed himself as an urban planner, intent onbeautifying a city linked to a grimy industrial past featuringsteel mills and slaughterhouses.

He ordered tree and flower plantings, developed an old pierand a city park as tourist attractions, and helped developersrepopulate the downtown area.

Daley pushed hard for Chicago's bid to host the 2016Olympic Games, but the effort fell short despite strong backingby President Barack Obama, a fellow Chicagoan.

And he has come under increasing criticism on severalfronts. His public approval rating in a Chicago Tribunenewspaper poll a few months ago sank to about a only one-thirdof respondents.

He was criticized by some for engineering the lease of thecity's parking meter system for what some said was a bargainprice. He also came under fire for using millions of dollars inproceeds from the privatization of the Chicago Skyway, ahighway linking the city with Indiana, and city parking garagesto shore up budget shortfalls.

Daley was interviewed by the U.S. Attorney's office inChicago during the federal investigation of the city's hiringpractices, though he was never implicated.

Two officials in his administration have been convicted ofschemes involving nepotism in hiring and illegally using cityworkers to perform campaign work.

Daley had made an unsuccessful run for mayor in 1983 beforewinning a special election to finish out the term of HaroldWashington, the city's first black mayor, who died in office. (Additional reporting by James Kelleher; Editing by LeslieAdler)