Fukufuji, the first Japanese-native to play in the NHL, entered to start the third in relief of Barry Brust. He faced five shots on goal, but allowed Wideman's goal 7:32 into the period that gave the Blues a 6-4 lead.
Brust allowed five goals in the first two periods.
The 24-year-old Fukufuji was recalled Friday on an emergency basis after Mathieu Garon was placed on injured reserve with a finger injury. Fukufuji became the first Japanese native to dress for a league game Dec. 16 against Dallas in another emergency stint.
Wideman also assisted on a second-period goal by Keith Tkachuk and on Martin Rucinsky's score in the first - both on the power play.
The Blues took the lead for good on Doug Weight's goal late in the second period. His fifth of the season gave the Blues a 5-4 advantage. Weight also assisted on Rucinsky's goal and helped set up Wideman's score.
Rob Blake's power-play goal with 5:12 made it 6-5.
Blake gave the Kings a brief 3-2 lead when he Scored 97 seconds into the second period.
Michael Cammalleri started the scoring 3:31 into the game with his 17th goal of the year.
Martin Rucinsky scored at 8:24 in the first to tie it before Tom Kostopoulos gave the Kings a 2-1 lead just over six minutes later.
Notes: D Christian Backman returned to the Blues' lineup after sitting out seven games. He injured his right knee December 26 at Nashville. ... It was coach Andy Murray's second game against the Kings, who fired him last spring, since taking over the Blues. St. Louis won 5-2 on December 21 in the first meeting. ... Saturday's game interrupted a string of seven road games for St. Louis, which went 2-1 in the first three games and play at Phoenix, Anaheim, Los Angeles and San Jose in a six-day span starting Monday.