She reportedly edged out Sen. Karen Keiser of Kent for the position.
Nelson will succeed Sen. Ed Murray who is leaving office soon to begin his new job as mayor of Seattle.
A former state representative, Nelson ran unopposed for her Senate seat in 2010. She serves on the Ways and Means Committee and was the lead Democrat in negotiations with Republicans on this year’s Capital Budget.
“I am honored to have been elected as leader by the Senate Democrats,” Nelson said in a statement. “We have a diverse caucus, but I believe I was elected by my colleagues because my foremost goal is to do what I was sent here by my constituents to do – work for them. I demonstrated my inclusive leadership style during the budget negotiations last year, and I intend to make that a focal point of my tenure as leader.”
Nelson takes charge of a caucus which is shrinking in number and influence in the Legislature.
When the Legislature convenes in January, the caucus will have 23 members as two other Democratic senators – Rodney Tom of Medina and Tim Sheldon of Potlatch – will continue to huddle with 24 Republicans in the Majority Coalition Caucus.
One of her chief tasks in 2014 will be to recruit candidates and pick up seats in the fall elections.
Nelson represents the 34th legislative district, which is comprised of parts of Burien, North Highline, Maury and Vashon Islands, and West Seattle.