He was brought up in a home where country music almost exclusively played (he is still fond of it today). He would sing harmonies with his family and learned how to play guitar, which his father also played. Once he began playing guitar for other people, around the fifth grade, he knew he wanted to be a performer. He was in several bands during his school days including a cover band that played a notable collection of rock artists (Rush and Kim Mitchell being notable contributors to their repertoire).
In the fourth grade, Robertson entered the gifted program at Churchill Heights Public School. Robertson's first run-in with Page, who was a year ahead in the same gifted program, was when he unknowingly "stole" Page's best friend. It would be several years before the two would really speak to each other. Page saw Robertson at a Harvey's restaurant after a Peter Gabriel concert and was surprised to find that Robertson was also a fan. This ultimately led to them talking and becoming friends.
Robertson attended Woburn Collegiate Institute with Page, and around the twelfth grade, realized he needed to focus on passing his courses to get into university, believing his goal of being musician was somewhat of a "pipe dream". It was around this point when he began playing with Page. The two became counsellors at Scarborough Schools Music Camp in the summer of 1988, and spent a lot of time together, singing songs and playing guitar. Page was flattered that Robertson knew some of his songs, which he had learned after acquiring a copy of a tape Page had made. Page was also impressed by Robertson's ear for singing harmony. Robertson ultimately turned to Page when he was scheduled to play at a benefit and his band had just broken up. The two played the benefit and in the process, formed Barenaked Ladies. He was accepted to York University, but dropped out after only half a year, choosing to devote his time completely to the band. He and Page spent the next two years building the reputation and following for Barenaked Ladies, joined along the way by Andy and Jim Creeggan, and Tyler Stewart.
Robertson contributed to the writing for the band from their first album. Much of his contribution initially came in the way of co-writing with Page. As the years have passed, Robertson has written more and more on his own (and also more and more with Page). He credits Jason Plumb in part for changing his perspective on songwriting, in that instead of trying to write one great song, he would commit to writing a certain number of ideas and they might not all be great, but parts of the songs would sometimes fit together into great songs. As well, Plumb encouraged Robertson to simply come up with an idea that fascinates him, and then to analyse it. The first song he wrote with this method was "When I Fall", based on the concept of "a window washer who's afraid of heights".
Besides Tyler Stewart, who doesn't typically write, Robertson is the only other band member who has not written and recorded songs outside of the Barenaked Ladies for himself in the form of a side project. Robertson has preferred to spend creative energy outside the band in co-writing and producing songs for other people (including Andy Kim and Jason Plumb).
In 2008, Ed Robertson guest co-hosted Daily Planet on Discovery Channel for several weeks while one of the regular hosts was away.
Robertson had two brothers and two sisters; his brother Doug died after crashing his motorcycle in June 1993. The experience had an impact on Ed personally; this came through in his songwriting. The song "Am I The Only One?", which he was writing about his future wife at the time, ended up being about his brother's loss; the song "Leave" is about the image of his brother haunting him in hotel rooms while on tour; and the song "Tonight is the Night I Fell Asleep at the Wheel" is was based on Robertson's wondering what his brother was thinking about in his last moments.
Robertson is fan of video games, and claims to have had almost every console system released since he was a child. He usually brings several consoles and many games on tour with him. Robertson is a fan of the popular machinima series Red vs. Blue, lending his voice to the series to voice , during a time travel episode. Originally for a one-off episode, Captain Flowers was re-introduced in late , 4 episodes before the announced finale. Rooster Teeth Productions has also made special videos, using Red vs. Blue characters, to be shown at Barenaked Ladies shows.
Robertson has several tattoos. The first one he got was on his right deltoid — a stylized Canadian flag with a green maple leaf and diagonal red bars. The next one he got was a Mercator projection of the continents of Earth circling his left deltoid. For his next tattoo, he visited a shop in Portland, Oregon run by Matt Reed. Reed enhanced the Canadian flag, and recoloured the map. He also added a third tattoo; a jumping fish, on Robertson's left arm, above the map. At his next session, Robertson got a band of acorns and Oak leaves on his right arm, below the flag (possibly also from Reed). Robertson decided to exclusively use Reed for his tattoos, and has said that he gets a new one every time he is in Portland. Reed has also designed t-shirts for the band. He e-mailed Reed photos of both arms (each having a band and a single image, in about the same place) and asked him to design a way to tie everything together. Reed enhanced the existing tattoos by framing the fish with a nautical themed frame, and the flag with a natural wooden themed frame, and adding backgrounds. In 2004, on the Au Naturale tour, Robertson added a dragonfly across part of his chest while in Portland.
Robertson won Humber College's inaugural Euterpe Award at the close of the 2005 Humber Songwriting Workshop. In his honour, the school named a scholarship after him for their summer songwriting workshop.
Having an interest in acting, Robertson had a brief appearance in Charlie's Angels 2, which was offered to him by director Joseph McGinty Nichol, who had directed Barenaked Ladies' video for "One Week". Robertson had a larger role in the independent Canadian film Love, Sex and Eating the Bones, which was directed by childhood friend Sudz Sutherland.