Ned Golubovic added 13 points and eight rebounds for the Bulldogs (5-6).
Keith Shamburger had 13 points for the Spartans (8-4), who had their three-game winning streak snapped.
Steed capped his night with two fast-break dunks in the final 3:08 and also was a big part of the defensive effort that limited Adrian Oliver, the WAC's leading scorer, to 15 points. Oliver entered averaging 25.8 points.
San Jose State used an 8-0 run to tie it at 47 with 9:47 left, but Fresno State responded with a 7-0 surge. The Bulldogs never trailed in the second half.
Fresno State led 33-29 at halftime.