NASHVILLE (AP) - Former U.S. senator and actor Fred Thompson was remembered Friday for his booming voice, sense of humor and sincerity.

At a public memorial service in Nashville, U.S. Sen. John McCain recalled how Thompson's funny, slightly subversive asides on the Senate floor made sometimes tedious proceedings more bearable. McCain said Thompson was a natural campaigner who didn't run for office just to play a senator but believed he had a responsibility to solve America's problems.

"He had such natural authority and charm and ease with people," McCain said. "Americans knew he was the real deal."

But Thompson sometimes found politics frustrating. Sen. Lamar Alexander recalled Thompson joking that he "missed the sincerity of Hollywood."

Thompson, who died Sunday at age 73 in Nashville after a recurrence of lymphoma, appeared in feature films and television, including NBC drama "Law & Order." Speaking of Thompson's first act ing role in the movie "Marie," McCain said, "Fred is listed as playing himself. That's who he always played, in movies and in public life."

Marie Ragghianti, whose story of exposing a Tennessee cash-for-pardons scheme was the basis of the movie, said she first saw Thompson when he worked as Senate counsel on the Watergate hearings. Later, she knew he was the attorney she needed to represent her after she was fired for exposing corruption.

She joked that, "I should have known from the start when he represented me that he saw me as a one-way ticket to Hollywood."

The two remained friends and she jokingly noted one lasting influence he had on her life: "I, a lifelong, born-and-raised, baptized and spoon-fed Democrat, now have two registered Republican sons, compliments of Fred Dalton Thompson."

Ragghianti and others recalled how the 6-foot-6 Thompson always filled a room with his commanding presence.

"Anyone who ever knew Fred Thompson knew him to b e a dynamic, charismatic man of uncommon charm," she said.

Thompson's brother Ken Thompson, recalled how the two always played jokes on each other. When Fred Thompson ran for president in 2007, his brother says he told him, "I have every intention of following in the footsteps of my hero, Billy Carter. And I'm going to produce Kenny Beer" - a reference to Billy Beer, promoted by President Jimmy Carter's brother.

Alexander, who took Thompson's Senate seat after he retired, said one of the reasons Thompson was a success was because he worked hard.

"For many, my saying that will come as a little bit of a surprise," he said, "because Fred was notoriously easy-going."

The two knew each other for nearly 50 years, Alexander said. "We will miss his common sense, his conservative principles, his big laugh and his booming voice."

After the public memorial, a tribute for friends and family was scheduled in Thompson's hometown of Lawrenceburg to be followed by a private burial service.