The Lions (8-16, 5-6 Ivy League) pulled away in the middle of the second half with a 14-1 run to lead 64-49 and led by double digits until Desmond Cambridge's 3-pointer for Brown made it 75-66 with 5:43 to go.
Brown (11-13, 4-7) got as close as 82-78 on Brandon Anderson's 3-point play with 1:27 left and Obi Okolie's 3 got it back to four at 86-82. But Columbia made 9 of 10 from the foul line in the final 1:35 to hold on.
Smith was 13 of 14 from foul line and Stefanini was 3 of 6 from 3-point range for the Lions. Nate Hickman added 16 points and Quinton Adlesh scored 10.
Cambridge had 26 points and 10 rebounds and Anderson scored 23 for the Bears.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.