Dr. McDonald died in 1967, and the board of regents quickly promoted Dr. Richard W. Setzer, vice president of academic affairs, to the presidency. 
When Richard Setzer assumed the presidency in March 1967, Lamar University was almost 44 years old. During the previous 43 years the school had only three presidents. The long administrations of presidents Bingman, Gray and McDonald had given time for the dreams of these men to become realities. Dr. Setzer would live only two years after he took office, and his successor, Dr. Frank A. Thomas, would resign after serving only three years.
The five years covering the brief administrations of these two presidents saw the continuation of the building program, the leveling of the enrollment boom, the start of the first doctoral program, the establishment of branch colleges and another name change. The late 1960s and early 1970s saw the end of the college-age population explosion that had caused Lamar and many other colleges and universities to grow rapidly. During the period, Lamar's enrollment plateaued between 10,000 and 11,000 students.
In September 1969, Lamar University opened its first extension center in Orange, with classes held in the old Tilley Elementary School.
In 1970, Lamar was authorized to offer its first doctoral degree program, the doctor of engineering. A dream shared by many became a reality on May 3, 1971, when Gov. Preston Smith signed a bill changing the name of Lamar State College of Technology to Lamar University.
In 1971, the Texas Legislature passed legislation authorizing Lamar University to operate a two-year educational center, enabling students to take two years of course work on the Orange campus. Later that year, the Tilley School building at LU-Orange was destroyed and a spirited communitywide fund-raising effort netted more than $250,000 for the purchase and renovation of the former Sabine Supply Co. building on Front Street. Classes began at this site in the fall of 1971.
Dr. Joe Ben Welch was director of the Orange Center. He later became a dean and provost, before becoming the first president of LU-Orange.
Dr. Frank Thomas resigned from the presidency on May 30, 1972. The board named Dr. John E. Gray to the presidency for a second time. Dr. Gray, who had earlier served Lamar for nine years, lead the university in its 50th Anniversary celebration the following year.
In 1975, Gov. Dolph Briscoe authorized appropriations to facilitate the merger of Port Arthur College with Lamar, and Lamar University-Port Arthur was established, with Dr. Sam Monroe as dean. Situated along the banks of the busy Intracoastal Canal that separates Port Arthur from the shores of Lake Sabine, the original Port Arthur College opened its doors in 1909.
In 1976, the family of the late businessman and philanthropist, Edgar W. Brown Jr., donated the family mansion and grounds to Lamar University. Named The Brown Center, LU-Orange operates the facility as a conference and special events center for the use of Lamar and the citizens of Southeast Texas.
