Two years after a hard-fought campaign left him 90 votes shy of a seat on the Cambridge City Council, urban planner Sam Seidel said in an interview yesterday that he will make a second run for the council this November.

The entrance of the 40-year-old Inman Square resident, whose 2005 runner-up finish in the council race was his first entrance into elective politics, adds the first strong challenger to the current field of nine incumbents. All councillors are elected city-wide through a single ballot on which voters rank nine of the candidates running in their preferred order.

In the interview, Seidel said that his two areas of emphasis will be “making sure that we are providing every kid with an excellent education” and “tackling the high cost of housing” in the city. He said that these two issues will play a large part in determining what Cambridge will look like “10 or 20 years in the future.”

Seidel, who has a masters degree in urban planning from the Graduate School of Design, added that he also hopes to push environmental concerns on the council, and that this is one area where Cambridge should set an example.

“We can’t be a leader on everything, but on environmental stuff it’s very clear we have to set the bar high and set it way out in front of us,” said Seidel, who went to college in Berkeley, Calif., a city noted for its environmentalism. “We’re the perfect size, we have plenty of resources, and we have lots of bright ideas. Cambridge ought to set a model for other cities to follow.”

Local political analyst Glenn S. Koocher ’71 said in an interview that Seidel is “highly credible” and his candidacy will be “a potentially winning one.”

“Sam has emerged as a very thoughtful candidate—progressive and reasonable but also very thoughtful,” said Koocher, a former Crimson staff member.

Koocher said that because of the way elections are conducted, “a large number of people have a favorite candidate, and obtaining city council votes often means wrestling them away from someone else.” But he added that Seidel might have a slight edge in winning over votes because his natural supporters, progressives, “are more loyal to their ideas than they are to individuals.”

Seidel’s decision to join the race, which he had been considering for at least the past several weeks, came the day after the resignation of State Senator Jarrett T. Barrios ’90. City Councillor Anthony D. Galluccio, who has consistently received the most votes in council elections since 1997, is considered to be one of the leading candidates for the seat.

Should Galluccio exit the council race—in order to devote more funds to a state senate campaign, for example—his absence would drastically increase the chances of a non-incumbent winning a council seat. Galluccio would, however, be legally allowed to serve concurrently as both a state senator and a city councilor.

Seidel’s candidacy could also pose a challenge to freshman Councillor Craig A. Kelley, a frequent critic of both City Manager Robert W. Healy, Cambridge’s chief executive, and the other councillors. Kelley and Seidel share much of the same political base: middle-class, progressive voters concerned about education reform and environmental issues.

But Seidel said in the interview that he would take a different approach to pursuing his agenda if elected, and that one of his top priorities is creating “a new dynamic on the council.”

“We need to work to reinvigorate our public discussion through our elected bodies,” Seidel said. “We want more cooperation and collaboration among councillors, and one of the things I can bring to the council is an ability to work with people to build consensus toward solutions.”

Kelley welcomed Seidel to the race in a brief interview yesterday, saying that “city councillors should always have to work hard for their jobs,” and “the more people concerned about [schools and the environment] the better.”

“City councillors...should never, ever take their seats for granted,” Kelley said.

—Staff writer Paras D. Bhayani can be reached at pbhayani@fas.harvard.edu.

—Staff writer Nicholas K. Tabor can be reached at ntabor@fas.harvard.edu.