Born Thomas LaBeff in rural Arkansas in 1935, roots-rock legend Sleepy LaBeef sang in church as a child. At home he listened to recordings by gospel pioneer Sister Rosetta Tharpe, and he absorbed plenty of blues and hillbilly music while selling watermelons in the street with his father. In the mid-50s he moved to Houston and began playing honky-tonks; he also cut some sides for XERF, the famous million-watt “outlaw” radio station that broadcast from across the Mexican border. After a few sessions with various small labels, he signed with Columbia in 1964; in 1971 he had a minor country hit with “Blackland Farmer” on Sun. Today LaBeef’s repertoire is estimated at over 5,000 songs, and at 67 his power is undiminished: he roars, growls, and implores in a muscular basso profundo that’s forceful but emotionally nuanced. On countrified rockers like Johnny Cash’s “Big River” or Lefty Frizzell’s “She’s Gone, Gone, Gone” he combines backwoods loneliness and rough-hewn optimism, and his vibrato and silken intonation on Tom T. Hall’s “May the Good Lord Never Show You the Back of His Hand” counteract its sadness with unwavering faith. LaBeef, an abstemious man who tolerates no profanity in his presence, rarely summons the requisite nastiness for low-down blues. But while his genre-jumping medleys can seem dilettantish, his ten-minute workouts on classics like Tharpe’s “Strange Things Happening in This World” or Roy Hamilton’s “You Can Have Her” are spellbinding reminders of his commitment to his music: his eyes glaze over, his massive frame sways, and he bellows out verse after verse, teasing and worrying the song into new dimensions. Saturday, October 19, 7:15 PM, FitzGerald’s, 6615 Roosevelt, Berwyn; 708-788-2118.