By the time the Australian left eight years later, the former Millwall man had made almost 300 appearances and scored 68 goals for the Toffees - not bad for a player that only cost A$3 million or so.
He went on to play in the United States, China, Australia and India, but, for many, he will forever be associated with the blue half of Merseyside.
Fans had their minds on other things at the time.
“He joined at the end of a difficult summer,” James Corbett, Everton fan, author, publisher and writer for OffThePitch.com, told The World Game.
“There was an ownership battle going on, Everton had just sold Wayne Rooney and all this came at the end of a 2003-04 season when Everton had their lowest ever points total - and I think expectations were as low as they were ever going to be for the club as a whole.
"Cahill’s arrival was kind of overlooked amidst this mass existential crisis."
Early signs were promising however.
“I thought he was as good a player as you are going to get from the Championship; he looked useful - he was technically quite good and put himself about - but I didn’t for a minute think he would evolve into an icon.”
He was one of the club’s best-ever signings, according to Dave Downie of Everton website and podcast The Blue Room.
“Everton's financial plight at the time of his signing meant the then-manager David Moyes had to work miracles,” Downie said.
“In regards to pound-for-pound and value for money, Cahill is head and shoulders above anyone else.
"It's difficult to answer this question without referring to the likes of Mikel Arteta, Tim Howard, Steven Pienaar or even Romelu Lukaku, but the impact Cahill had on the club cannot be seconded.”
The first decade of the 21st century was a mixed time for the club.
“It was a small squad and the centre-forward role was always an issue within it over a period of almost a decade,” Corbett recalled.
“After his first season, Tim would step in as an auxiliary centre-forward, but also drop back and play in midfield or play as a second striker. His versatility was a great virtue."
Plenty of English corner flags must be in a better state for Cahill not being around and attacking them after scoring. The celebration came after some fine and crucial goals.
“My happiest memory of Tim Cahill was a goal he scored in a 1-1 draw against Liverpool at Anfield,” Downie said.
“We were 1-0 down to our bitter rivals who were chasing their first Premier League title.
"They had taken the lead through Steven Gerrard and the game looked to be heading their way until Cahill stooped to head home in front of the 3,000 Evertonians with just a couple of minutes left.
"It was a typical Cahill goal - he was a master at finding the smallest of spaces in the penalty area to get a header in on goal. He was also a thorn in Liverpool's side and loved scoring against them.”
For Corbett, it is Cahill’s final strike for Everton in the 2012 FA Cup quarter-final against Sunderland that stands out.
“It was a Saturday afternoon and Goodison was packed - there were 8000 visiting fans - and Everton battered Sunderland, but found themselves a goal behind.
"It was tense. The referee wasn’t giving us any favours. There was a bit of nastiness in the air.
"Then Tim got us an equaliser. He sort of twisted in mid-air and got a lot of power behind the ball in a microsecond to head it in.
"It was a typical Cahill goal, but, physically, very difficult to pull off and the TV replays don’t do it justice. I was dead level with it. I remember the exaltation as he came towards us to punch the corner flag.”
A few months later and he was on his way to New York.
“He was past his peak and I think there was an unspoken acknowledgement that the time was right for him to move on,” Corbett said.
“As ever, you never really appreciate what’s good until it’s no longer there. Because he never won anything, I think he’s probably underappreciated.
"For me, he’s one of the great Everton players of the current century and his achievements on the pitch - both for Everton and internationally - and stature off it certainly outstrip some of those who are considered ‘legends’.”
Downie holds the Australian in similarly high regard.
“Tim Cahill is probably Everton's most revered modern-day former player, possibly second only to Duncan Ferguson in the popularity stakes since the club's most successful period in the 1980s.
"Players who have a knack for scoring big goals for their teams are worth their weight in gold.”