Having hit the post when clean through in the first half, the 32-year-old forward made amends with 10 minutes left, shooting past Jamie Langfield to secure the points.
And Wright said: "Steven is excellent on and off the pitch, he's a big personality.
"By his own admission he doesn't get enough goals, but I think that's down to the work he does outside the box.
"He does so much unselfish work bringing other people into play, that he is sometimes not in the positions he should be to score.
"But he's a real leader for us and is a winner.
"He's not afraid to have a go at people on the pitch, sometimes too much and I have to curtail him a bit.
"But I don't mind it because he gets the people around him going. He brings us so much quality."
Aberdeen manager Derek McInnes was unhappy that his side failed to capitalise on first-half chances missed by MacLean and Gary McDonald.
"It was a very disappointing afternoon,” he said. “We caused ourselves problems and got off the hook.
"We got away with a couple and there were enough warnings for us to cut out the sloppiness.
"We should have dealt with the goal better and, for Steven MacLean to have that room to put it away, isn't good enough.
"Although we hit the bar (through Andrew Considine) and finished the half better than we started, I felt we huffed and puffed.
"There wasn't much in the game, there wasn't an awful lot of quality.
"St Johnstone are a team who always make it difficult. They are well organised, hard-working and play with aggression.
"When you play them you need that bit of quality and I don't think we had enough of that."