The Argentine came off the bench at halftime to send his side on its way to a pivotal 3 points, much to the delight of the home support.
The win moved the Catalan club 9 points clear of Atletico Madrid in second place with three games left to play — but a superior head-to-head record hands them an unassailable lead.
It’s the fourth title Barcelona has won in the past five years and it kept alive hopes of a prestigious treble this season.
Ernesto Valverde had promised not to rest key players for the fixture against relegation-threatened Levante, but there was one notable absentee from the starting lineup.
Messi, who now boasts 10 domestic titles, was seemingly rested for the first half with perhaps one eye on Wednesday’s Champions League semifinal first-leg against Liverpool.
However, the Argentine star was introduced at the break with the scores level after a frustrating first half in which Barcelona failed to convert a host of chances.
Predictably, it was Messi who made the breakthrough just after the hour mark after a sustained period of pressure.
The 31-year-old demonstrated his trademark quick feet to control the ball before sending it on its way to the bottom corner.
The forward has been pivotal in his team’s success this season and looks set to be named La Liga top scorer with 34 goals already to his name.
His closest competition comes in the form of teammate Luis Suarez, who sits second in the standings on 21.
The win is Barcelona’s 26th title, but they still trail Real Madrid’s record tally of 33 domestic crowns.
However, Zinedine Zidane’s side has struggled for consistency since star player Cristiano Ronaldo left the club, and it is languishing 15 points behind Barcelona in third.
The Nou Camp was rocking in celebration as fans watched their side wrap up the title race at home for the first time since 2010.
Valverde can now focus on the remaining cup competitions as he looks to guide his team to three major honors this season.
Barcelona face Liverpool in the Champions League and will look to win the Copa del Rey against Valencia on May 25.