Portrayed by James Darren, he is a holographic representation of a 1960s-era Las Vegas Rat Pack–style singer and entertainer, as part of a program run in the holosuites at Quark's bar.

Fontaine represented a source of romantic advice for the crew, helping to get Odo (René Auberjonois) and Kira Nerys (Nana Visitor) together as well as aiding Quark (Armin Shimerman) and Julian Bashir (Alexander Siddig) to move on from their love of Jadzia Dax (Terry Farrell).

Executive producer Ira Steven Behr had long sought to introduce a Rat Pack-style character to Star Trek: Deep Space Nine since the fourth season,[1] as he was a lifelong fan of 1960s-era Las Vegas and the music of that period.

[1][3] During the production of the fifth season episode "A Simple Investigation", it was decided to insert the scene that Behr and Wolfe had previously created.

Behr was unsure how to write the character into the show until it became apparent that it could be included as part of the relationship between Odo and Kira Nerys in the episode "Children of Time".

[2] Rather than film an individual scene, he decided that an entire 1960s-era Las Vegas themed episode should be created, resulting in the production of "His Way".

[5] Meanwhile, Behr and a friend attended a memorabilia show at the Beverly Garland Hotel in North Hollywood, where James Darren was signing autographs.

He loved playing the character while reading it ten times to absorb the personality enough to avoid having to memorize lines.

[7] Darren came in for casting and began talking about knowing where to source the appropriate tuxedos, and that he could wear a pair of Dean Martin's shoes that he owned.

He forms part of a new Rat Pack-style Las Vegas bar program owned by Doctor Julian Bashir (Alexander Siddig).

[9] Afterwards, Odo (René Auberjonois) seeks some advice in private from Fontaine about his feelings for Kira Nerys (Nana Visitor).

[10] During the second appearance of the character in "Tears of the Prophets", Bashir and Quark (Armin Shimerman) run Fontaine's program in an attempt to cheer themselves up after realising that they will never have a chance with Jadzia Dax (Terry Farrell) because of her relationship with Worf (Michael Dorn).

Later, while the Federation troops are under siege by the Jem'Hadar, Bashir plays Fontaine's recording of "I'll Be Seeing You" over a sound system to raise morale.

[13] As a result of him losing his leg during the siege, in "It's Only a Paper Moon", Nog (Aron Eisenberg) keeps playing that song in private upon his return to Deep Space Nine.

[14] Ezri Dax (Nicole de Boer), the station's counselor, has concerns with Nog living in a fictional world and speaks to Fontaine, who explains that he has a plan to rectify the situation.

Shortly after he resumes his role back on the station, Nog returns to Fontaine to inform him that he has convinced Quark to leave the program running continuously to allow Vic to have a life of his own.

[16] During the finale of Deep Space Nine, "What You Leave Behind", Quark passes the time during the attack on Cardassia Prime by playing Go Fish with Fontaine.

[18] That episode was ranked as the third best of the series by Gem Wheeler for Den of Geek, who called Fontaine the "ideal holographic host" on the show.