Ten previously unaired episodes were added during its syndicated run. Two are from season five, and are consecutive, and eight are from season six. Season five's two episodes are: Mr. Belvedere: The Dinner (1989) and Mr. Belvedere: The Attic (1989). Season six's eight episodes are: Mr. Belvedere: Love Fest (1990), Mr. Belvedere: Donuts (1990), Mr. Belvedere: Runaways (1990), Mr. Belvedere: The Pageant (1990), Mr. Belvedere: The Baby (1990), Mr. Belvedere: Bad Marsha (1990), Mr. Belvedere: Home (1990) & Mr. Belvedere: Mumsy (1990).

On Gilbert Gottfried's podcast "Gilbert Gottfried's Amazing Collassal Podcast" episode "Mini-ep #100" Gottfried revealed his was once on the same studio lot used for the taping of Mr. Belvedere. Gottfried witnessed Christopher Hewett being rushed to a hospital. Given Hewett's size Gottfried assumed he suffered a heart attack. After making inquiries, Gottfried learned from one of the Belvedere crew members that Hewett did not suffer a heart attack. Rather Hewett accidentally sat on his testicles while filming an episode of Belvedere.

The 1985 series was the fourth attempt to adapt the 1947 novel Belvedere by Gwen Davenport and subsequent film series starring Clifton Webb for television. In 1956, a pilot was produced but was rejected by the networks. In 1959, a second pilot starring Hans Conried was also rejected. In 1965, a third pilot starring Victor Buono also failed to sell.

While doing the series, Bob Uecker continued his work as a full time broadcaster for the Milwaukee Brewers. As a result, filming of episodes was scheduled to accommodate Uecker's broadcasting responsibilities.

Mr. Belvedere was the first prime time sitcom to feature a character with AIDS. In the season two episode, Mr. Belvedere: Wesley's Friend (1986), that aired on January 31, 1986, a classmate of Wesley's is removed from school after it becomes known that he contracted AIDS from a blood transfusion. The episode was similar to that of Ryan White, the Indiana teenager who successfully sued his school after being expelled when he contracted AIDS from a blood transfusion. ABC was initially reluctant to air the episode, but Christopher Hewitt insisted on it.

The show was not on ABC's fall line-up for the 1987-1988 TV season, but was added when Max Headroom (1987) was abruptly canceled.

In the pilot episode, George Owens' occupation is identified as that of a construction worker. In subsequent episodes, the character's occupation was changed to a newspaper sports reporter and, over the course of the series, a television sportscaster. The change was likely made to reflect Bob Uecker's real life career as a sportscaster that audiences largely associated him with.

The producers debated whether or not Mr. Belvedere should be actually writing his diary during his voice-over or whether he would be merely go over what he had already written.

Among 117 episodes of the series, all six characters were in 112 of the 117 episodes. Three characters appear in every episode: title character Mr. Belvedere (Christopher Hewett), Marsha Owens (Ilene Graff) and Wesley Owens (Brice Beckham).

The series' pilot episode, Mr. Belvedere: Stranger in the Night (1985), originally aired on Friday evening, March 15, 1985. Cinematographer George Spiro Dibie won a Primetime Emmy for Outstanding Lighting Direction (Electronic) for a Series for his work on the episode.

Mr. Belvedere's full name is Lynn Aloysius Belvedere.

In a recurring gag, the character of Angela Shostakovich (Michele Matheson), Heather Owens' dimwitted best friend, constantly calls Mr. Belvedere by the wrong name. Some of the names include "Mr. Bombardier", "Mr. Bell Bottom", "Mr. Butterfinger", "Mr. Velvetta", "Mr. Baby Boomer", Mr. Bell Pepper", "Mr. Bumper Car", "Mr. Belafonte" and "Mr. Bunny Hopper".

The photograph of Mr. Belvedere and the Owens family was taken during the final scene of the episode Mr. Belvedere: G.I. George (1988). It is the closing credits' longest lasting clip at each conclusion.

Actor Rob Stone was 23 years old when he was cast as the teenaged Kevin Owens.

George always referred to Mr. Belvedere as "Big Guy".

The scene of Mr. Belvedere turning off the television with a remote control that appears at the end of the opening credits is from the second season episode Mr. Belvedere: The Teacher (1986)

The series' memorable theme song, "According to Our New Arrival", was written by Judy Hart-Angelo and Gary Portnoy and was originally intended for a series entitled Help that was eventually scraped by ABC. In 1985, an unnamed studio singer performed the song for the pilot episode of Mr. Belvedere. When the series was picked up by ABC, a re-recorded version performed by blues singer Leon Redbone was used as the theme (varying instrumental version of the song were used during the closing credits). In 2007, Gary Portnoy released a previously unheard version of "According to Our New Arrival" on his album, Destiny.

The series is based on the 1947 novel, Belvedere, by Gwen Davenport about an arrogant genius who answers an ad to be the butler for a family of three bratty children as a guise for writing a novel about a community filled with gossips and busybodies. The novel was adapted into the comedy film Sitting Pretty (1948), featuring Clifton Webb as Mr. Belvedere. Webb would reprise the role in two more feature films, Mr. Belvedere Goes to College (1949) and Mr. Belvedere Rings the Bell (1951).

Among the series many guest stars was crooner Robert Goulet, future Oscar nominee and Emmy Award winner James Cromwell, baseball player Reggie Jackson, football player Bubba Smith, Dr. Joyce Brothers, Susan Anton and Tony Danza (both in cameo roles), Jason Bateman and Seth Green.

Mr. Belvedere began its run in March 1985 on Friday nights, eventually becoming a part of ABC's popular TGIF lineup. It remained there for five seasons until declining ratings prompted ABC to move the series to Saturdays in September 1989. In December 1989, part way through the sixth and final season, ABC pulled the series from the schedule and shelved the remaining eight episodes. In July 1990, ABC aired the two part series finale. The eight unaired episodes were eventually aired in syndication.

At the start of the series, Kevin Owens is a high school junior. In reality, actor Rob Stone was 23 years old when the series first aired. Likewise, actress Winifred Freedman, who portrayed Wendy, a classmate who harbors an unreciprocated crush on Kevin, was 28 years old when she first appeared on the series.

Rob Stone, who portrayed the role of the eldest Owens child Kevin, directed part one of the series finale Mr. Belvedere: Mr. Belvedere's Wedding: Part 1 (1990). He went on to direct, produce and write other television series and films.

Then-child actress and singer Stacy Ferguson, who later became well known under the moniker Fergie, appeared in the season 2 episode Mr. Belvedere: Valentine's Day (1986). Ferguson portrayed the role of Beth, a seemingly sophisticated classmate of Wesley's who has a crush on him.

Episode, Mr. Belvedere: G.I. George (1988)'s final scene, just before closing credits start is where the group photograph of housekeeper, Mr. Lynn Aloysius Belvedere, acted by Christopher Hewett (standing behind the Owens family, he lowered his head for photo focusing). Setting on a couch, [from left to right] George Owens, acted by Bob Uecker, Marsha Owens, acted by Ilene Graff, Kevin Owens, acted by Rob Stone, Heather Owens, acted by Tracy Wells and Wesley T. Owens, acted by Brice Beckham. The family photograph was originally picked by Marsha Owens. The photograph is taken, 2 to 3 seconds at the near end of opening credits and is on longer and still, as the closing credits shows names of full cast and crew, writers, creator, producers, directors, production staff and guest stars, then the photo changes as lesser popular names appear.

The theme song is sung by Leon Redbone.

The two part series finale, "Mr. Belvedere's Wedding", aired on ABC on two consecutive Sundays - July 1 and July 8, 1990 - after ABC had pulled the series from its lineup in December 1989. In the finale, Mr. Belvedere meets Louise Gilbert, an animal behaviorist. After a whirlwind courtship, the couple announce their engagement. Mr. Belvedere assures the Owens that he will remain in Pittsburgh and continue to work for them. However, during the wedding ceremony, Louise tells Mr. Belvedere that she must go to Africa for work. Mr. Belvedere then makes the tough decision to leave the Owens family and start a new life with his wife.