A first half header from captain Kwak Tae-hwi and second half goals from Brazilian striker Rafinha and midfielder Kim Seung-yong secured Ulsan a deserved victory over their Saudi opponents who were also chasing their maiden continental crown.
With a crowd of 42,153 creating lively atmosphere at Ulsan Munsu Stadium, Kim Ho-gon's side ensured the AFC Champions League title returned to Korean hands for a third time in four years to also seal a place at next month's FIFA Club World Cup in Japan.
"Ulsan have had to wait for a long time to come to final so I told the players we must win the game and to do that we must play a normal game," said former Korea Republic defender Kim Ho-gon.
"The players created a lot of pressure in the first half and all of the players played their part.
"After the first goal the players felt they could win and they made some mistakes and allowed Al Ahli to create some attacks. At half-time I talked to the players and the second half was very good.
"I am so happy for the players. They wanted to play in the FIFA Club World Cup and it is the same for me. This is the happiest day in my coaching career."
Having seen his side outplayed for the majority of the 90 minutes, Al Ahli coach Karel Jarolim was also quick to hail Ulsan's comprehensive victory as the Saudi League side again suffered defeat at the hands of Korean opposition in the continental final having lost the 1986 Asian Club Championship decider to Daewoo Royals.
"Maybe some of our important players that we expected to perform didn't perform very well. Not because they didn't want to, but because Ulsan are a strong team and they were playing at home. The players did their best, but Ulsan are a strong team and they deserved to win," said Czech coach Jarolim.
"In the first half we missed a lot of chances and conceded a lot of fouls. After the first goal we had a few chances to score at least a goal in the first half, but the strikers didn't work well with the ball.
"And after the second goal the players then lost concentration and didn't focus on the match so Ulsan had a lot of control of the ball and Ulsan were able to score a third goal."
Ulsan's Korea Republic international midfielder Lee Keun-ho, meanwhile, was named AFC Champions League MVP after contributing four goals during the campaign.
Having opened his account with the decisive goal against Japan's Kashiwa Reysol in the Round of 16, Lee Keun-ho scored in three consecutive games leading up to the final as Ulsan first disposed of Saudi Arabia's Al Hilal in the last eight and then Uzbekistan's Bunyodkor in the semi-finals.
"I can't express how happy I am," said the 27-year-old. "I have no words to describe how happy I am. I am so happy that I am able to give a present to the coach, Kim Ho-gon.
"I won the MVP award which did not expect. This is the biggest individual prize of my career and now I want to become AFC Player of the Year."