The actor is due to star in a fifth Indiana Jones film, which will be released in 2019.
Ford told the BBC: "I've always thought there was an opportunity to do another. But I didn't want to do it without Steven [Spielberg].
"And I didn't want to do it without a really good script. And happily we're working on both.
"Steven is developing a script now that I think we're going to be very happy with," he said of Spielberg, who is directing the film.
Spielberg directed the four previous Indiana Jones films, which were all produced by Star Wars creator George Lucas.
Ford first appeared as Indiana Jones in Raiders of the Lost Ark, released in 1981.
He then starred in three subsequent films, most recently in 2008's Indiana Jones and the Kingdom of the Crystal Skull.
Ford was speaking to the BBC ahead of the DVD release of Star Wars: The Force Awakens, the film in which he reprised his role as Han Solo.
When asked whether Han Solo, who is killed in the film, could return in some form to future movies in the franchise, Ford replied: "Anything is possible in space.
"I wanted Han Solo to sacrifice himself for the good of the other characters to bring some gravitas to the story."
Speaking about his involvement in the film, Ford said: "I was very pleased to have the opportunity to work with the other characters, to work on a script that I had real confidence in, with actors that were a dream to work with, with a director that had a very sure and generous hand, and it was altogether a pleasure."
But Ford said he does not feel an emotional connection to the characters he plays.
"I hope I bring an emotional understanding of the characters and something the audience will recognise," he said.
"I want the audience to experience the character, not to feel that they know him but to be involved in seeing what happens to him."
Star Wars: The Force Awakens became the UK's biggest film of 2015 after just 16 days of release, with takings of Â£94.06m.

31 March 2017 Last updated at 09:10 BST
That's because she has a very strong type of anxiety called selective mutism.
But she's started taking a special music class which has helped her to speak at school.
Meet Ruweyda by watching our video.
You can find out more about what anxiety is and how it can affect you by reading our guide, here.

The England captain, unbeaten on 95 overnight, reached 101 not out off 198 balls before retiring.
St Kitts stuttered to a draw with a second innings of 76-7, after England had declared on 379-6 at tea.
Another two-day game follows but with an agreement for England to bowl and bat for 90 overs regardless of wickets.
The first Test against West Indies starts in Antigua on 13 April.
Cook, 30, has scored an England-record 25 Test tons but has not reached three figures in his last 31 Test innings.
His last century for England in any match was 154 (retired out) against Australia A in Hobart on 6 November, 2013.
Cook, who was dropped from the one-day squad on the eve of the World Cup, is looking to reassert himself as batsman and captain before England attempt to win back the Ashes in July and August.
Ian Bell also retired on 59 as England replied to St Kitts first innings total of 59 all out.
Pace bowlers Liam Plunkett and Mark Wood, initially left out of the side, shared the new ball in the second innings and both were among the wickets as coach Peter Moores used 14 players.
Kent off-spinner James Tredwell was the pick of the bowlers with 3-35.
He said: "We'd have liked a sterner contest but you play the cards you are dealt and get on with it.
"A little bit of a sterner contest would have been handy, but it's time in the middle for us."
Harrison Ford has said he did not want to star in a new Indiana Jones film without director Steven Spielberg.
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Ruweyda is seven years old and has only recently said her first words at school.
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Alastair Cook hit his first England century since November 2013 on day two of their warm-up match against a St Kitts & Nevis Invitational XI.