Ed joined the Chiefs as a number four draft pick in 1964. He started in a few games in 1964 as a tight end and defensive end. In 1965, after gaining 80 pounds with an off-season weight program, Ed started for the Chiefs as a defensive tackle for the next three years. He made an impact on the defensive line right away, & enjoyed two productive seasons before sustaining a shoulder injury in the sixth game of the 1966 season. However, in 1967 Lothamer made a strong comeback. He played for another three seasons, including both Super Bowl games.

Ed retired after the 1970 Super Bowl, but came out of retirement for the 1971 & 1972 seasons. Ed played back-up behind Curley Culp and played in all 14 regular season games, plus the inter-divisional battle against Miami in 1971.

Today, Ed is owner of Concrete Placement Company, a concrete pumping firm with offices in North Carolina, Oklahoma, Missouri, Arkansas, and Kansas.