"For me, the George Washington example of serving eight years and riding out of town on a horse and never returning has great appeal," the Tennessee Republican said in 2002, the twilight of his eight-year Senate career.
Now, five years later, he is a well-known TV actor who finds himself on the verge of a real-life presidential bid, seemingly recruited by activists hungry for someone to fill what they see as a conservative void among the top-tier Republican hopefuls.
"I think he is very close to announcing he is going to run," CBS News chief Washington correspondent Bob Schieffer said. "I am told by people around him that he has made the decision. It's just a question of when he's going to announce."
Numerous signs point to a Thompson candidacy, and a summertime announcement is widely expected, although people close to him caution that he has not made a final decision about running.
Never mind that he basically already is.
Thompson is hiring staff, speaking to conservative groups, writing online columns on topics of the day and staking out positions on issues like the Senate immigration overhaul. He also is testing his pitch on the Internet.
"It's important to the future of this country that (Republicans) have somebody that can win in November," Thompson said in a recent online interview. "People are looking for somebody who can talk straight to them. That's what I hope I bring to bear."
His expected entrance into the already crowded Republican field could dramatically shake up the wide-open race. But it is unclear who among the strongest contenders, Rudy Giuliani, John McCain and Mitt Romney, would be affected the most.
Not yet a full-fledged candidate, Thompson has found himself competitive with them in national popularity polls. That is likely due in part to his acting role as district attorney Arthur Branch on NBC's popular drama "Law & Order."
The conservatives who make up a big part of the Republican base have found fault with Giuliani, McCain and Romney for varying reasons and for months now have been searching for a candidate to embrace.
Thompson's backers bill him as the perfect person — the one truly conservative candidate in the mold of Ronald Reagan who can beat the Democratic nominee in November 2008. Rep. Zach Wamp of Tennessee called Thompson "naturally conservative with a down-home sense of humor and a confidence about who he is."
In the Senate, Thompson was considered a reliably conservative vote. The American Conservative Union gave him a lifetime rating of 86 out of 100. He fiercely backed the Iraq war, worked to limit the federal government's role, supported banning a late-term abortion procedure and voted for President George W. Bush's tax cuts.