Making his first start following 259 days out with a cruciate ligament tear, the 28-year-old captained the side and came through 71 minutes unscathed, before making way to a standing ovation from the Signal Iduna Park faithful.
"Obviously I was absolutely thrilled to play again, to be back at the stadium and experience that feeling," Reus told bundesliga.com after the game. "I'm pleased we could top that off with a win at home."
Reus' last game in a Dortmund shirt was in the DFB Cup final win against Eintracht Frankfurt on 27 May. His last Bundesliga appearance came a week earlier on the final day of the 2016/17 season, when he scored twice in a 4-3 triumph over Werder Bremen. Many expected him to be eased back in gradually over the coming weeks - not Peter Stöger.
Watch: Reus reflects on his Dortmund comeback
"He's been training normally with the team for a couple of weeks now," explained Dortmund's head coach. "When a player of his quality is ready to play, I'd much rather have him on the pitch from the start. He's an exceptional player. He makes things happen, and makes other players around him better. We've waited a long time and we hope that he stays healthy. All in, it was a good day for us."
Dortmund's win - their second in as many matches - propelled the Ruhr district giants up to third in the Bundesliga standings, only a point behind second-placed RB Leipzig. Chelsea loanee Michy Batshuayi - who had a hand in all three goals against Cologne last time out - opened the scoring on his home debut, before Reus' replacement Mario Götze wrapped up the win in added time.
"It wasn't our best performance, but it's always important to win when you're not playing well," Reus said. "We missed chances when we were on top, perhaps we could have scored a second earlier, but we put the game to bed in injury time. We know we still have a lot of hard work ahead of us."
Dortmund host Serie A side Atalanta in the first leg of their UEFA Europa League Round of 32 tie on Thursday, before facing Reus' former club Borussia Mönchengladbach on Bundesliga Matchday 23, buoyed for both by the performance of the comeback kid: Matchday 22's Man of the Matchday.