Sproule had missed the previous two games with a hamstring injury but bounced back to score a superb goal in the 11th minute on at the Global Energy Stadium, sending a shot from the edge of the 18-yard box into the top corner.
It was his fourth goal in as many starts for his new club since his move last month from Hibernian, as Ross extended their unbeaten run to seven games.
For Sproule, the move is going according to plan, and he said: "I'm enjoying my football at the moment. I took a wee knock which kept me out for two games but I came back in - I'm just glad to be playing and get the win.
"But all credit goes to the lads, they turned in two good performances while I was out of the team.
"This is the reason I came to the club, to play games and pick up three points every weekend - and that's what I'm doing at the minute."
Describing his goal, Sproule added: "I fancied a whip at it and luckily for me it flew into the top corner.
"I don't care who scores, we've got the three points.
"I'm in a rich vein of form. I was trying to put it in off the post, there was no other place I could have put it."
The Northern Irishman has already made himself a mainstay at County, in contrast to his second spell at Easter Road where he failed to establish a regular starting spot.
Although the 31-year-old has no rancour about his time at Hibs second time around, he is relieved to be playing a major part now.
"I didn't get playing at Hibs," he said.
"It wasn't to do with my form, it was a personal choice by the manager.
"I respected him though because he's got a decision to make. I played in the Championship for four years and won a cup with Hibs and I came up here with nothing to prove to anybody."
St Johnstone defender Callum Davidson admired Sproule's goal but also felt it was not their day.
He said: "It was a fantastic finish, I'm not quite sure he meant it to stick it in that top corner but it was a good finish.
"We kind of put pressure on them after that but nothing really fell for us.
"We maybe looked a little bit lethargic in the last third.
"I thought the effort was there; it was just one of those games - you just have to pat Ross County on the back and say they defended really well."
Davidson added: "It was a big game for us going into the Celtic game on Tuesday.
"If we got a result today it would have put us in a prime position.
"It is not an easy place to come to and the pitch wasn't great either.
"We were all pretty angry and upset in the changing room after the result, that shows the lads care.
"Celtic are in the middle of a big run at the moment, we'll see what team they put out.
"We had a couple of good results against them in the league.
"But it's up to us to recover properly and go again on Tuesday."