He did not begin playing the double bass until the age of 20, graduating from Yale University School of Music with a Masters degree in 1976. He has also studied at Rutgers University. He teaches at Sarah Lawrence College, The New School, and SIM (School for Improvised Music).
Helias has performed with a wide variety of musicians, including Ray Anderson, Gerry Hemingway, Anthony Braxton, Dewey Redman, Barry Altschul, Anthony Davis, Don Cherry, Ed Blackwell, Carlos Ward, Nana Vasconcelos, Cecil Taylor, Muhal Richard Abrams, Oliver Lake, Julius Hemphill, Marilyn Crispell, Arthur Blythe, Abbey Lincoln, Marcel Khalife, Simon Nabatov, Don Byron, Marty Ehrlich, Mark Dresser, Ellery Eskelin, Cuong Vu, Mose Allison, and the J. B. Horns.