A brace from playmaker Igor Coronado in each half on top of a Welliton strike was enough for Sharjah to claim domestic honours in almost a quarter of a century, while Leonardo da Silva and Sebastian Tagliabue were on target for Al Wahda.
Sharjah cannot be caught by second-placed Shabab Al Ahli because of their superior head-to-head record. The Dubai side sit three points off the summit with the final round of fixtures to be played on Saturday.
Sharjah, who had a lead of 11 points at one stage, were handed their first defeat of the season when they stumbled 3-2 against Al Wasl last Sunday, but Abdulaziz Alyassi's men persevered against Al Wahda.
The last time Sharjah won the domestic league was in the 1995-1996 season - their fifth title. The title triumph earns them direct entry into the 2020 AFC Champions League.
