In Canada, the Disney's One Too block aired on Family Channel, a specialty channel that has long been associated with The Walt Disney Company due to its carriage of Disney-produced feature films and television series (and formerly served as the Canadian broadcaster of Disney Channel's original programming, replaced by a Canadian version of Disney Channel).
In January 1998, UPN began discussions with The Walt Disney Company (owner of rival network ABC) to have the company program a daily two-hour children's block for the network. However, attempts to reach a time-lease agreement deal with Disney were called off one week after negotiations started due to a dispute between Disney and UPN over how the block would be branded and the amount of E/I programming that Disney would provide for the block; UPN then entered into discussions with then-corporate sister Nickelodeon (both networks were owned by Viacom) to produce the new block. That February, UPN entered into an agreement with Saban Entertainment (which at the time was part-owner of Fox Family Worldwide, the parent subsidiary of Fox corporate parent News Corporation that produced competing block Fox Kids) – which distributed two series already seen on the UPN Kids block around that time, Sweet Valley High and Breaker High – to program the Sunday through Friday morning block.
In March 1998, UPN resumed discussions with Disney and the following month, The Walt Disney Company and UPN came to an agreement to provide Disney-produced programs on the network every Sunday morning (from 8:00 to 10:00 a.m.) and on Monday through Fridays (from 3:00 to 5:00 p.m.) The block was originally announced under the working title "Whomptastic", though the name was changed prior to the debut of the block for greater brand identity (incidentally, "whomp" was used as a pejorative term in the Disney-produced animated series Recess, one of the series that would end up part of the new block, as a substitute for "sucks").
The new lineup was later renamed Disney's One Too in July 1999, formatted to serve as a companion block to ABC's existing children's block Disney's One Saturday Morning. The block debuted on September 5, 1999, replacing UPN Kids, which ended its run the day before (on September 4) after four years. Compared to the format of One Saturday Morning, One Too differed in that, instead of incorporating hosted segments, short gag segments from the shows featured in the block Fox, The WB, UPN, and independent stations (such as Sabrina: The Animated Series, Doug and Recess, all of which – along with a few other series – were originally aired on One Saturday Morning) were usually shown, often preceding the start of each program, and after commercial breaks. The block also featured a different opening sequence, using more futuristic buildings and a theme similar to that used on One Saturday Morning. Many shows formerly featured on Disney's One Too continued in reruns on Toon Disney and Disney Channel.
In September 2002, the One Too branding was dropped as a result of the rebranding of the ABC block from One Saturday Morning to ABC Kids; although the UPN block was unbranded, the Disney.com website referred to it under the brand Disney's Animation Weekdays. The block ended on August 29, 2003, with the time periods being turned over to UPN's affiliates; this left UPN as the only "big six" broadcast television network without children's programming, and one of only two major commercial broadcast networks that did not air a children's programming block (the other being Pax TV, which discontinued its Pax Kids lineup in 2000, before reviving children's programming as Ion Television through the 2007 launch of Qubo).
UPN was not the first "big six" network to drop children's programming: NBC became the first to drop kids shows entirely in August 1992, when the network launched a live-action block for teenagers called TNBC (however, children's programming returned to NBC in 2002, through a time-lease agreement with Discovery Kids). To date, ABC (which dropped the ABC Kids block in 2011, and replaced it with the syndicated live-action family-oriented E/I block Litton's Weekend Adventure), CBS (which replaced the Cookie Jar TV block with a similar live-action E/I block, CBS Dream Team, in 2013), Fox (which dropped its 4Kids TV block on December 27, 2008), The CW (which replaced the Vortexx block with another similar E/I block, One Magnificent Morning), and MyNetworkTV (which has never run children's programming since it launched in 2006) are the only television networks that do not air children's programming or whose E/I program content is not strictly aimed at that demographic.
In most markets, UPN affiliates carried the block Monday through Fridays from 3:00 p.m. to 5:00 p.m. and Sundays from 8:00 a.m. to 10:00 a.m. (in all time zones). However, some stations (such as WWOR-TV in New York City, KCOP-TV in Los Angeles and KTVD in Denver) aired the weekday block in the morning from 7:00 to 9:00 a.m.