Murray is establishing an exploratory committee and will work in the coming months to build the foundation for a campaign. Because of rules for state lawmakers, Murray soon will be unable to raise money until the Legislature completes next year's session.
"I want to put down my marker," Murray said. "I want to start having conversations with people."
Murray said he is focused on his duties in the state Senate, where Democrats have chosen him to be their new leader. He acknowledged that he may not be able to launch his mayor candidacy if the coming session goes too long, perhaps into the summer months.
It is expected to be a crowded field in the mayor's race. Seattle City Councilman Tim Burgess has already entered the campaign.
Murray wouldn't talk specifically about his views on current Mayor Mike McGinn. He said they've disagreed on methods for building a consensus on topics like the viaduct replacement, and Murray said his time in the state Legislature has shown how he can build support for contentious issues.
Murray has long been the lead advocate in the state Legislature on gay rights issues, and he was one of the chief proponents of the same-sex marriage law this past year.
This coming session presents a new set of challenges for Murray. He recently was chosen to lead the Democratic caucus, but two senators in his party have indicated they may work with Republicans to choose a different majority leader.
Because of that turmoil in the chamber, Murray fears there could be gridlock and delays. Meanwhile, other candidates in the mayoral race will be out campaigning and raising money before Murray completes his work in Olympia.
"I will be at a disadvantage," Murray said. "Anyone else in this race will have raised a lot more money."