The station first signed on the air on November 18, 1973 as WSNL-TV, originally licensed to Patchogue. The station was founded on the premise of there being over three million people living on Long Island who were underserved by local television news coverage; with all the network affiliates based in Manhattan, it was rare to see more than one or two news stories a day focusing on Long Island.

WSNL went on the air with two daily newscasts: a half-hour early evening broadcast and an hour-long newscast at 10 p.m., in addition to coverage of high school sports; it also carried some off-network reruns and first-run syndicated programming. One of the more noteworthy series among this batch was Phil Donahue, which had been in national syndication since 1970, but was not available in the crucial New York City market until that point, and after the station's demise, would not find another outlet until WOR-TV (channel 9) acquired the local rights to the program in 1976, followed by WNBC Channel 4 in 1977. The station also carried games from the short-lived New York Stars of the World Football League in 1974.

The station also produced several locally produced programs, among these offerings were: Chef Nicola (a cooking show hosted by Nicola Zanghi); Home Handyman (a home repair show hosted by future congressman David G. McDonough); Captain Ahab (a weekday kids' cartoon show hosted by George McCaskey, as the Captain); Ahab and Friends (a three-and-a-half hour weekend kids' show similar to WNEW-TV's Wonderama; also hosted by McCaskey, which featured cartoons, puppets, games, contests, and other assorted entertainment for its young audience); Mary Kelly's Puppet Party (another children's program); Long Island Tonight with Richard Hall (a variety show); and The Fairchilds of Long Island (a rare locally produced soap opera which featured local actors).

The news department of 18 people used the very earliest form of portable videotape equipment, which only ran off AC or inverters in cars, and not off batteries. This greatly restricted local video coverage to the length of a power cord. In that era, before satellites were used for television distribution, the station employed a courier who used a motorcycle nightly to race from Manhattan with a tape of national and international news stories for the late newscasts.

After a year of operation, inadequate revenue resulted in the cutback of its news programming to five-minute briefs that aired several times a day and the department shrunk to just a few employees before the station went bankrupt and signed off for the last time on June 13, 1975.

Return to air

WSNL returned to the air again four-and-a-half years later, on December 4, 1979, with a daily broadcast day running from 4:00 p.m. to midnight. The station ran some old movies, brokered programming, and religious shows. The following month on January 30, 1980, an electrical fire nearly destroyed the station's studios, forcing WSNL to shut down again, this time until July 1980.

Upon returning to the air, the station began running a mixed independent/subscription television format featuring programming from Wometco Home Theater. WSNL aired a morning movie from WHT between 11 a.m. and 1 p.m., then ran encoded color bars until 3:45 p.m., followed by unencoded color bars until sign on at 4 p.m. for four hours of commercial programming. This lineup consisted primarily of old movies, film fillers, public affairs shows, and a local newscast that was anchored by Karl Grossman and Joan May. At 8 p.m., WSNL ran WHT programming until sign-off, which was usually around 1:30 a.m. or later. On Saturdays, WSNL operated for four hours beginning at 1 p.m. (featuring old movies, public affairs shows and wrestling), followed by WHT programming from 5 p.m. until sign-off. Sunday was slightly different, as WSNL would sign on at 8 a.m. with two hours of religious shows, then sign off at 10 a.m., it resumed programming at 1 p.m. with general entertainment programming running until 5 p.m., followed by WHT programming running until sign-off. In January 1981, Wometco Enterprises bought WSNL and began simulcasting Newark's WWHT (now WFUT). However, WSNL would occasionally break away from WWHT-TV during its entertainment schedule to run a local public affairs show, then rejoin WWHT.

In a corporate deal, Kohlberg Kravits Roberts took over Wometco along with a couple other broadcasting companies. In 1985, WSNL and WWHT discontinued the general entertainment and subscription programming in favor of music videos, with the parent station becoming known as "U-68". By the fall of 1986, the stations became WHSI and WHSE when KKR sold its stations to a variety of owners. WWHT and WSNL were sold to the Home Shopping Network, whose programming ran on both stations for the next fifteen years.

In the late 1990s, HSN's broadcasting arm Silver King Television planned to switch its stations to a general entertainment independent format, with WHSE/WHSI slated to switch in 2001. Late in 2000, however, USA Broadcasting, which Silver King was renamed after Barry Diller purchased HSN and its other holdings (merging it with USA Network), decided instead to sell its stations to Univision Communications (The Walt Disney Company, owners of ABC owned-and-operated station WABC-TV channel 7, had been the leading bidder for the USA stations but were outbid by Univision at the last minute). WHSI switched programming from AIN/UATV, networks that generally affiliated with low-powered stations in other markets; it then became a charter affiliate of Univision's new secondary network Telefutura (which rebranded as UniMás in January 2013) on January 14, 2002, with its call letters being changed to WFTY (the call letters had been formerly used by Washington, D.C. CW affiliate WDCW as an independent station, which represented that station's channel 50 allocation).

Analog-to-digital conversion

WFTY discontinued regular programming on its analog signal, over UHF channel 67, on June 12, 2009, as part of the federally mandated transition from analog to digital television. The station's digital signal remained on its pre-transition UHF channel 23, using PSIP to display WFTY's virtual channel as 67 on digital television receivers, which was among the high band UHF channels (52-69) that were removed from broadcasting use as a result of the transition.