"Oh, can it be, upon a tree, the Savior died for me?" he sings from a John Newton hymn, his raw and rumbling voice describing how music fits into ministry. "My soul is thrilled, my heart is filled, to think he died for me."
Mr. Shea celebrated his 100th birthday Feb. 1, and the songs that defined his career still burst out in a signature bass-baritone that can quiet a room in an instant.
He worked with Dr. Graham for more than half a century, making him one of the world's most recognized voices: He's sung live in front of an estimated 200 million people, and he's still making appearances without his longtime partner.
"When they ask me to sing these days, they're just being kind, you know?" Mr. Shea said.
His wife rejects that idea.
"When everybody else sings, it's a personality singing," Karlene Shea said. "When he sings, something else comes over you -- the words, the message and you forget he's standing there."
Though he's about a decade older than Dr. Graham, Mr. Shea is in far better health. Aside from a heart attack a few years ago, Mr. Shea's only ailment is a painful back. He walks -- mostly with the aid of a walker -- and still visits all the restaurants near his mountainside home.
While Mr. Shea hasn't driven a vehicle since he was 95, he noticed a year ago that his driver's license had expired. Wanting to keep an updated form of identification, he went down to the local office, passed the vision test and won a new license.
"I don't feel 100," he said in an interview at his home in Montreat, about 15 miles east of Asheville.
Mr. Shea's life is mostly quiet these days, spent in Montreat with his wife. He often watches reruns of Dr. Graham's sermons that he says still move him.
Though he lives just a mile away from his famous partner, he and Dr. Graham mostly speak by phone. Dr. Graham's health has been slipping for years and he has been hospitalized several times in recent years.
Though Mr. Shea's career is largely behind him -- his last major production was a country-and-western album in 1997 -- he still sings at senior celebrations and other events connected to Dr. Graham's ministry.
Born in Winchester, Ontario, he grew up singing in the choir of his father's Wesleyan church.
After moving to New York City, the budding virtuoso had several chances to perform on secular radio but shied away after auditioners wanted him to sing songs such as To Hell With Burgundy .
Mr. Shea left for Chicago and started work at Moody Bible Institute as a singer on gospel radio.
It was there that Dr. Graham, just 21 years old at the time, first met Mr. Shea after hearing his voice on the airwaves.
Four years later, in 1947, Mr. Shea joined Dr. Graham's young crusade team, singing at an event in Charlotte and beginning a decades-long ministry that would reach to every state and every corner of the earth -- from North Carolina to North Korea.
Writing The Wonder of It All and reviving songs such as How Great Thou Art , Mr. Shea was at times given the moniker of "America's beloved gospel singer," riffing off Dr. Graham's role as "America's pastor."
He recorded more than 70 albums of gospel music and won a Grammy (he has been nominated 10 times). With a personality that strays from humble to bashful, though, Mr. Shea deemed his role in the ministry as "very insignificant" -- especially compared with his contemporaries.
"What I do is old-fashioned," Mr. Shea said. "It's the guitar these days. When they sing at Mr. Graham's meetings, it's pretty exciting. People clap, you know? So they look for me to come up before the message and sort of quiet them down."