The Saudi Arabian side sealed a 3-0 aggregate victory by beating Urawa Reds 2-0 in Sunday's second leg of the continental showpiece.
They therefore become the seventh and last team to qualify for next month’s Club World Cup in Qatar, in which Liverpool will compete for the first time since 2005.
Al Hilal will enter the competition in the second round and face ES Tunis on December 14.
The winners of that match progress to meet Flamengo in the semi-finals after the Brazilian outfit won the Copa Libertadores on Saturday.