When the actress takes on comedies, such as the new “Tijuana Jackson: Purpose Over Prison” and the much better “Support the Girls,” she treats every line with the high-stakes seriousness of a breakup. Hall gives consistently real performances that are, as a result, really funny.

Her muscular skill lifts the otherwise hard-to-believe “Tijuana Jackson,” a meh-ckumentary about a foul-mouthed black ex-con who wants to become a motivational speaker. “A life coach with a goon hand” is his offensive tag line, which he says many, many times.

Hall, who isn’t in enough scenes, plays his parole officer, Cheryl, and provides the funniest part of the film: She smokes a joint while driving Tijuana (Romany Malco) around Florida to hunt for jobs. It’s always a joy to watch a hardass let her hair down. The second-funniest bit of the movie is the frame: High school kids are making a 10-minute short film about Tijuana, who has been in a Miami clink for years. So we see his antics through the eyes of spoiled, upper-middle-class teens.

From there, the plot, such as it is, is meandering, and the stereotypical humor is been there, done that. In an early scene in the prison, a counselor has a linguistics expert translate Tijuana’s slang. That is a 40-year-old joke from “Airplane!”

It’s the directorial debut for Malco, who’s acted in such comedies as “The 40-Year-Old Virgin” and “Blades of Glory.” He also wrote the movie, edited it and stars. That work overload is probably why “Tijuana Jackson” the film — and the performance — is so unfocused. Tijuana is arrogant, delusional and swears a lot, but he’s not unique or eccentric enough to prop up a whole comedy.

As an actor, Malco shines best in scenes with the character’s dismissive family, particularly Momma (Lyne Odums) and his snide sister, Sharea (Tami Roman).

When he arrives home from prison to a small house whose overgrowth is taller than he is, he tells the camera he’s pumped for his welcome-home party.

“Party?!,” Momma says. “I’m supposed to celebrate you getting out of jail and let the whole neighborhood know my son’s … a felon!”

It’s a moment with heat and laughs. The rest of Malco’s movie is short on both.