Brock Lesnar has been WWE Universal Champion for 435 days.
WWE has recognized CM Punk's 435 day (434 on other databases) reign with the WWE Championship as the longest WWE Championship reign in modern WWE history. Brock Lesnar's WWE Universal Championship has been the Raw counterpart to the WWE Championship which is on Smackdown. As of Sunday, Brock Lesnar has tied CM Punk's 434 day record, and passed it Monday morning.
Lesnar is by far the most prolific WWE Universal Champion in history as Kevin Owens is the closest to his reign length with 188 days. In the modern era, John Cena had a 380 day reign as WWE Champion which is the closest to either CM Punk or Lesnar's number.
Lesnar has no match currently scheduled and last appeared when he won a cage match against Roman Reigns at the Greatest Royal Rumble event. His next match has been rumored for SummerSlam.
This weekend at Money in the Bank, four wrestlers from Raw have the opportunity to win a Money in the Bank briefcase which entitles them to a Championship match against Lesnar.