A Yeom Ki-hoon goal in the 59th minute saw Jeonbuk take the lead, with Brazilian midfielder Botti adding a second in the final seconds of the match for the Koreans to take a two-goal advantage into the second leg.
The match was evenly poised after 45 minutes of play with both teams feeling each other out, however the home side took the honours in the second half.
"It was a tough opening period," Jeonbuk coach Choi Kang-hee said.
"Al Karama were strong physically, stronger than we expected.
"We felt that they would fade in the second half and we know we had to take our opportunities when they came."
Winger Yeom seized his opportunity when Al Karama defender Anas Al Khouja made an error in defence, with Yeom running on to a long ball from midfield before curling his shot into the net.
"It was great to score," said the 23 year-old.
"But we still have to play well next week.
"We had problems in the first half. We thought they would be defensive but they were more attacking than we expected," Yeom added.
"At half-time we knew we had to improve our movement in the second half and eventually they would tire. We are confident for the second leg."
The best in Asia
Jeonbuk's confidence grew even further when substitute midfielder Botti put the hosts 2-0 up in the dying stages, taking advantage of some loose defending in the Karama box to send his shot home from close range.
The result puts the Korean team in the box seat with 90 minutes left to play before an AFC Champions League winner is crowned, however it comes as a surprise, as Jeonbuk are sitting last in their domestic league with one match to play in the season.
"Today we won 2-0 so the second leg should be a little easier," said Choi.
"We are the K-League's representative team so I want to show everybody that the K-League is the best in Asia."
The teams have a one week break before the second leg of the final, which will be played in Syria on November 8.