Luke is voiced by Yūjirou Ōtsuka (大塚 雄史郎, Ōtsuka Yūjirou) in Japanese, and by Dominic Allen in English.
Luke has blonde shoulder-length shaggy hair covered with white baseball cap and green eyes, and has tattoos on both his arms and hands.
Luke wears a gray tanktop covered with a red sleeveless zipped vest that has a white skull picture and V.S.S.E. logo's. He wears white shorts with pale gray color addition. He wears green and yellow socks and a pair of red sneakers. He also wears a two pale-colors beaded necklaces, a brown handband with white spikes on right wrist and a brown rubbered handband on left wrist.
Luke and Marc are well-known in the V.S.S.E. for having superhuman speed. To ensure newer agents are capable of meeting more stringent challenges against tougher enemies, Luke and Marc are issued with gas-actuated pistols (a V.S.S.E.-modified IMI Desert Eagle Mark XIX) carrying 9 .50 AE rounds per magazine in addition to the required battery and aptitude-oriented Crisis mission training.
Luke and Marc were at a hotel to help their direct officer, Robert Baxter retrieve a silver briefcase (under possession by Wild Dog) left behind by a murdered V.S.S.E. auditor three months prior to the events of the game. When Luke and Marc attacked the drudges, their cover was blown, and the agents had to fight Wild Dog throughout the air and land with helicopters and motorcycles. Wild Dog ejected the briefcase out-of-range before blowing himself up for the fourth time.
The briefcase was retrieved by Keith Martin in a deserted island containing Wild Dog's factory as one of its facilities, and its contents are data revealing that their superior Robert is the traitor among the V.S.S.E.. With Keith taking over as the partners' direct officer, Luke and Marc eventually put a stop to the now treacherous Robert's madness as they send him falling off a cargo plane ready to fire a drug-filled missile, but not before Robert shoots the plane's engine to send it crashing down into the ocean. Before stopping Robert, Luke and Marc had to fight Wild Fang, who is armed with a modified right leg which can fire missiles and solar generators attached to his back which can create a solar energy orb, inside a cave.
As the youngest of the franchise's protagonists, Luke tends to be impatient and talkative, often showing excessive desperation when showing willingness to complete his task at hand given to him from the directorship, surpassing Evan Bernard's. Keith didn't like Luke's impatience, as evidenced in a scene during the True Mastermind expansion of Time Crisis 5. Luke tends to be attached a bit too closely to Catherine, but in spite of his impatient demeanor, Luke is up to any challenge he and Marc are given.
|Japanese version||English version||Remarks|
|せっかくのリゾートホテルなのにな......||What a waste of a perfectly good resort hotel.||Luke O'Neil, during the prologue of the game|
|犬退治前に、軽く準備運動しようぜ||What do you say to a light warm-up before we get down to dogcatching?||Luke O'Neil, before the start of the game|
|ははっ！こりゃワイルドドッグもこっぱみじんだな！||Ha! Not even Wild Dog could've made it through that!||Luke O'Neil, after the tactical missile on the roof is destroyed by the V.S.S.E. helicopter|
|キャサリン 裏切り者はロバートだった（マーク: 俺たちはこれからキースと一緒にロバートを追う）||Cathy, Robert was the one behind all this! (Marc: We're following after him with Keith.)||Luke O'Neil, after learning that his negotiator Robert Baxter is the V.S.S.E. traitor|
|キリがないぞ！（キース: ふせろ！）||They're endless! (Keith: Get down!)||Luke O'Neil, when more Elite Soldiers gather around Wild Fang before Keith Martin blasted them with a missile|
|おいおい......マジかよ||Whoa whoa, are you kidding me?||Luke O'Neil, when Wild Fang began charging a solar weapon|
|島だ！ちょっと探検していこうぜ！||It's an island! Let's go check it out!||Luke O'Neil, after being relieved that Catherine Ricci survived the helicopter crash|
- Luke is currently the only V.S.S.E. agent who does not wear a jacket or coat at all.
- Luke's vest and the skull symbol resemble that of the 1988 TAD Corporation video game Cabal (published by Taito in Japan and Fabtek in North America and Europe) because the protagonists of Cabal wear vests and the skull symbol is the symbol of Cabal main menu screen.