A $1,000 a month passive income from ASX shares is a big target, but I think it becomes less intimidating when it is treated as a project rather than a single investment decision.
For me, the starting point is not asking which share has the biggest dividend yield today. It is asking what kind of portfolio could still be paying income years from now.

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How I would approach it
If I were trying to build $1,000 a month from the ASX, I would think about the portfolio in layers.
The first layer would be reliable dividend payers. These are the companies I would expect to keep paying through different market conditions.
That could include names like Telstra Group Ltd (ASX: TLS), Transurban Group (ASX: TCL), Woolworths Group Ltd (ASX: WOW), and Commonwealth Bank of Australia (ASX: CBA). They all have different risks, but they also sit in parts of the economy that people use regularly: communications, toll roads, groceries, and banking.
I think that kind of everyday relevance is useful when building an income portfolio.
Add some higher-yield exposure carefully
The second layer would be higher-yield shares or income-focused ETFs.
This is where investors might look at stocks such as HomeCo Daily Needs REIT (ASX: HDN) or Harvey Norman Holdings Ltd (ASX: HVN), depending on valuation and outlook.
An ETF such as Vanguard Australian Shares High Yield ETF (ASX: VHY) could also help spread the risk across a wider basket of dividend-paying companies.
I would be careful here. A high yield can be attractive, but it can also signal pressure on the business or a dividend that may not be sustainable.
That is why I would prefer a mix rather than relying too heavily on one or two generous dividend payers.
Use growth to fund future income
The third layer is the one I think investors often overlook.
To build a serious passive income stream, I would want some capital growth as well.
A portfolio that only focuses on income from day one might grow too slowly. By including some businesses with the ability to lift earnings and dividends over time, the income target can become easier to reach.
That could include quality compounders such as Wesfarmers Ltd (ASX: WES), Goodman Group (ASX: GMG), or even a broad ETF such as the Vanguard MSCI Index International Shares ETF (ASX: VGS).
These may not provide the highest income today, but they can help the portfolio become larger over time. A larger portfolio can then produce more income later.
What size portfolio is needed?
The maths depends on yield. A portfolio yielding 4% would need around $300,000 to generate $12,000 a year, or $1,000 a month.
At a 5% yield, the required portfolio falls to $240,000.
At 6%, it falls again to $200,000.
Personally, I would be cautious about building the whole plan around a 6% yield. I think a more balanced target of 4% to 5% is healthier because it leaves room for quality and diversification.
Foolish takeaway
For me, building a $1,000 a month passive income from the ASX is about building a layered portfolio: reliable dividend payers, some carefully chosen higher-yield exposure, and enough growth to keep pushing the portfolio forward.
Done patiently, with reinvested dividends and regular additions, I believe the ASX can be a powerful place to build a meaningful second income over time.