White, who has played two regular season games in his career, started on a line with Ryan Dzingel and Viktor Stalberg.
Head coach Guy Boucher dressed 12 forwards and six defencemen against the Penguins, who lead the series 3-2, after opting for seven defenders in a 7-0 Game 5 loss.
The 21st overall pick in the 2015 draft, White spent this season at Boston College (33 points in 35 games) before joining the Senators AHL affiliate for three games in late March.
He made his regular season NHL debut on Apr. 3 versus Detroit.
White took the place of defenceman Ben Harpur while Dzingel also replaced Tommy Wingels.