CONCORD -- City leaders past and present bid farewell to a longtime public servant on Tuesday night, welcomed a council critic to the other side of the dais, and cheered the return of the city's elder statesman, who will return as mayor 40 years after first holding the position.

In unanimous votes, the Concord City Council selected Dan Helix as mayor and Tim Grayson as vice mayor. In Clayton, longtime Councilwoman Julie Pierce was selected as mayor, and Hank Stratford will be vice mayor. Jim Diaz was also sworn in to join the Clayton council.

Helix, who served as mayor from 1972-74, returned to fill a vacancy in 2011 and finished first in a field of 11 candidates in the Nov. 6 election.

In 2013, Helix will focus on the Concord Naval Weapons Station development, improving the area around the downtown BART station and hopes to bring back a youth council in an effort to get the city's teenagers more engaged with city government.

Helix was sworn in along with Edi Birsan, a small-business owner who joins council after years of frequently commenting at meetings. Birsan finished second in the election.

It was also announced that Wednesday would be called "Bill Shinn Day" to honor the outgoing councilman. Shinn, who served on the council for eight years and was mayor in 2008, did not run for re-election due to health issues. Supporters modified campaign signs to thank the retired Contra Costa County Sheriffs' Office commander.

"For those that I couldn't convince and didn't get your vote over the years and support, that's my failing," Shinn said. "But nonetheless, I hope I represented all of you. It's a tremendous community."

State Sen. Mark DeSaulnier, state Assemblywoman Susan Bonilla and District Attorney Mark Peterson, all former Concord council members, were among those who thanked Shinn for his service to the city.

"I know that we didn't always agree on things, but you were always going to make the decision you thought was right," said former councilman and current District Attorney Mark Peterson. "That's the best thing we can have in our elected officials, somebody who looks at the situation or the challenge or the issue and then votes their conscience. You, I think, stood out in that respect probably more than any other council member I served with."

David DeBolt covers Concord and Clayton. Contact him at 925-943-8048. Follow him at Twitter.com/daviddebolt.