Joe Pesci (Lethal Weapon 2) Lethal Weapon 2 (1989)
Joe Pesci was forty-six when Lethal Weapon 2 opened in July 1989. He had spent the eighties in a kind of professional dormancy — the Best Supporting Actor nomination for Raging Bull (1980) had not produced the leading-man career anyone expected, and by 1985 he had effectively retired from acting and opened a restaurant in Bayonne, New Jersey. Once Upon a Time in America (1984) and a handful of supporting roles kept him in the trade, but the main act was over until two films arrived in the same eighteen months — Lethal Weapon 2 and Martin Scorsese's Goodfellas (1990) — and reactivated his career permanently.
Leo Getz was Joel Silver's idea
The Leo Getz character existed in the Black-Murphy spec, but he was smaller — a money-laundering witness in protective custody who survives the case. Producer Joel Silver had the instinct that the Riggs/Murtaugh dyad needed a third voice for the sequel, and that the third voice should be a fast-talking East Coast comic counterweight to the West Coast laconic of Gibson and Glover. Silver suggested Pesci, having seen him in Once Upon a Time in America, and director Richard Donner agreed within one meeting.
"I told Joel: this guy is the franchise. The minute Pesci opens his mouth, I knew we had a third Lethal Weapon, and a fourth, and probably a fifth." — Richard Donner, Empire oral history (2017)
Pesci shot LW2 in late 1988 through early 1989. Goodfellas shot through the spring and summer of 1989, with overlapping post on both films through fall. The Best Supporting Actor Oscar for Goodfellas arrived in March 1991, well after LW2 had already opened, but the trade press in summer 1989 was already calling Pesci's Leo "the breakout supporting role of the year." (wikipedia)
"Okay, okay, okay" was Pesci's
The verbal tic — "okay okay okay" — was not in the script. Pesci has said in interviews that it came out of nervous-witness improv during table reads and that Donner kept asking him to do more of it.
"I was trying to play scared. I kept saying 'okay okay okay' the way a guy who knows he's gonna die says it. Donner heard it once and said: do that every time you walk in a room." — Joe Pesci, Late Night with Conan O'Brien (1992 appearance, archived)
The pattern locks in across the film and becomes franchise-defining. By LW3 (1992) and LW4 (1998), Leo's "okay okay okay" is established as a verbal signature; the audience expected it the way audiences expect Murtaugh to say "I'm too old for this shit." (See Joe Pesci as Leo Getz.)
The structural role of Leo Getz
What looks like comic relief is doing structural work. Leo's "house with stilts on it" memory is the address that points the partners at Rudd;b10 b11 Leo's accidental tax-records research surfaces the Alba Varden as a ship rather than a woman.b22 The film's two key procedural breakthroughs come from a witness in protective custody at Murtaugh's kitchen table, not from surveillance or interrogation. Pesci's performance has to land both registers — comic-witness and structural-detective — and he does, mostly by switching modes inside single scenes.
"Leo Getz is the most important secondary character in any Lethal Weapon. He gives the partners both their leads and almost half their laughs. Pesci built him in a few weeks of pre-production and he became the franchise's third leg." — Mick LaSalle, San Francisco Chronicle retrospective (2018)
What followed
After LW2 and Goodfellas, Pesci's career went vertical. Home Alone (1990) and its sequel (1992) made him a family-cinema fixture. My Cousin Vinny (1992) gave him a leading role and is still cited as one of the most legally accurate courtroom films ever made. Casino (1995) reunited him with Scorsese for the third time. He returned for both Lethal Weapon 3 (1992) and Lethal Weapon 4 (1998); in LW4, Leo Getz becomes a private investigator and his backstory is folded into the family.
After 1999 he stepped back again, returning only for Scorsese's The Irishman (2019), which produced his fourth Oscar nomination. The Leo Getz character has been a touchstone for franchise fans for thirty-five years and is one of the most recognizable supporting performances of the late 1980s.