Sen.-elect Angus King, I-Maine, surprised no one Wednesday morning when he announced that he would caucus with the Senate Democrats, bringing the number in that caucus to 55 for the new Congress.

“I wanted to maintain my independence as long and as thoroughly as possible,” King said. He added that “it simply wouldn’t be practical” to not join either caucus.

“Affiliating with the majority makes the most sense,” particularly with a clear Democratic majority, King said.

King made the announcement at a highly anticipated news conference in the Capitol before the Republicans and Democrats each held leadership elections Wednesday morning.

The move affirms that, in effect, the Democrats made a net gain of two seats in an election where they were thought to be at risk of losing control of the chamber. The Democratic and Republican campaign committees both acted as though they expected King would be a de facto Democratic vote, but the relative success of the Democrats on Election Day reduced King’s leverage since his vote would not help determine the makeup of the chamber.

The 68-year-old King has positions on social, health and environmental issues that align him much more closely with the Democrats in the chamber, although he pledges to be an independent voice.

King worked for Sen. William Hathaway, D-Maine, in the 1970s, leading to some speculation he could seek a seat on the Health, Education, Labor and Pensions Committee. Republican Susan Collins, who will become Maine’s senior senator upon the retirement of fellow centrist GOP Sen. Olympia J. Snowe, said Tuesday that she felt she could work with King regardless of which side he picked.

“I certainly hope that he will make a decision to join our caucus. But regardless, I’m positive that he will not be an automatic vote for either caucus and instead will look at the issues on their merits and will attempt to reach across the aisle regardless of which side of the aisle he’s sitting on,” Collins said Tuesday before King’s announcement.

King has expressed interest in following Snowe onto the Commerce, Science and Transportation Committee, where she is a senior member of the panel and would have been in line to become the top Republican had she not decided to retire.

Alan K. Ota contributed to this report.