When Maria Bello joined NCIS in Season 15 as the brilliant and emotionally guarded Jacqueline “Jack” Sloane, fans immediately noticed her easy chemistry with Leroy Jethro Gibbs, played by longtime series lead Mark Harmon. That spark quickly reignited a familiar fan question: just how big is the age gap between the two stars — and would their characters realistically work as a romantic pairing?
In real life, Mark Harmon was born on September 2, 1951, while Maria Bello was born on April 18, 1967. That puts an age difference of roughly 15 and a half years between them. At the time Bello joined the series, Harmon was in his late 60s, while Bello was in her early 50s — a gap noticeable on paper, but far less so on screen.
What made the potential Gibbs–Sloane romance compelling wasn’t age, but emotional parity. Sloane was written as Gibbs’ equal: experienced, confident, and deeply scarred by her past. Rather than a traditional romance arc, NCIS opted for restraint, allowing subtle moments and unspoken understanding to carry their connection.
In the end, the show chose emotional respect over romance — and for many fans, that made their bond even more powerful.
